diff --git a/C968Project/Inventory.cs b/C968Project/Inventory.cs
index a3c959e..b590598 100644
--- a/C968Project/Inventory.cs
+++ b/C968Project/Inventory.cs
@@ -5,8 +5,8 @@ namespace C968Project;
 
 public class Inventory
 {
-    public BindingList<Product> Products { get; set; }
-    public BindingList<Part> Parts { get; set; }
+    public BindingList<Product> Products { get; set; } = new();
+    public BindingList<Part> Parts { get; set; } = new();
     
     public void AddProduct(Product product)
     {
diff --git a/C968Project/Part.cs b/C968Project/Part.cs
index e2fe568..6855a1f 100644
--- a/C968Project/Part.cs
+++ b/C968Project/Part.cs
@@ -8,4 +8,5 @@ public abstract class Part
     public int InStock { get; set; }
     public int Min { get; set; }
     public int Max { get; set; }
+
 }
\ No newline at end of file
diff --git a/C968Project/Program.cs b/C968Project/Program.cs
index 9207d58..fa80987 100644
--- a/C968Project/Program.cs
+++ b/C968Project/Program.cs
@@ -1,3 +1,4 @@
+using System.Runtime.CompilerServices;
 using C968Project.Views;
 
 namespace C968Project;
@@ -6,6 +7,40 @@ static class Program
 {
 
     public static Inventory Inventory = new();
+    public static int PartIdCounter = 2;
+    public static int ProductIdCounter = 1;
+
+    private static Part _testInhousePart = new Inhouse()
+    {
+        Name = "Inhouse part",
+        Min = 0,
+        Max = 100,
+        Price = 10,
+        InStock = 50,
+        PartID = 0,
+        MachineID = 2
+    };
+    private static Part _testOutsourcedPart = new Outsourced()
+    {
+        Name = "Outsourced part",
+        Min = 10,
+        Max = 100,
+        Price = 5,
+        InStock = 21,
+        PartID = 1,
+        CompanyName = "Chem Inc."
+    };
+
+    private static Product _testProduct = new Product()
+    {
+        Name = "Product",
+        AssociatedParts = new(){_testInhousePart, _testOutsourcedPart},
+        InStock = 500,
+        Max = 4000,
+        Min = 2,
+        Price = 5.45f,
+        ProductId = 0,
+    };
 
     /// <summary>
     ///  The main entry point for the application.
@@ -13,9 +48,19 @@ static class Program
     [STAThread]
     static void Main()
     {
+        Inventory.AddPart(_testOutsourcedPart);
+        Inventory.AddPart(_testInhousePart);
+        Inventory.AddProduct(_testProduct);
+
         // To customize application configuration such as set high DPI settings or default font,
         // see https://aka.ms/applicationconfiguration.
         ApplicationConfiguration.Initialize();
         Application.Run(new MainScreen());
     }
+}
+
+public enum ScreenOption
+{
+    ADD,
+    MODIFY
 }
\ No newline at end of file
diff --git a/C968Project/Views/AddModifyPartScreen.Designer.cs b/C968Project/Views/AddModifyPartScreen.Designer.cs
index bcee08c..5ae12f3 100644
--- a/C968Project/Views/AddModifyPartScreen.Designer.cs
+++ b/C968Project/Views/AddModifyPartScreen.Designer.cs
@@ -34,7 +34,7 @@
             idLabel = new Label();
             idTextBox = new TextBox();
             nameLabel = new Label();
-            textBox2 = new TextBox();
+            nameTextBox = new TextBox();
             inventoryLabel = new Label();
             inventoryTextBox = new TextBox();
             priceCostLabel = new Label();
@@ -69,6 +69,7 @@
             inHouseRadioButton.TabStop = true;
             inHouseRadioButton.Text = "In-House";
             inHouseRadioButton.UseVisualStyleBackColor = true;
+            inHouseRadioButton.Click += inHouseRadioButton_Click;
             // 
             // outsourcedRadioButton
             // 
@@ -80,6 +81,7 @@
             outsourcedRadioButton.TabStop = true;
             outsourcedRadioButton.Text = "Outsourced";
             outsourcedRadioButton.UseVisualStyleBackColor = true;
+            outsourcedRadioButton.Click += outsourcedRadioButton_Click;
             // 
             // idLabel
             // 
@@ -107,12 +109,12 @@
             nameLabel.TabIndex = 3;
             nameLabel.Text = "Name";
             // 
-            // textBox2
+            // nameTextBox
             // 
-            textBox2.Location = new Point(234, 127);
-            textBox2.Name = "textBox2";
-            textBox2.Size = new Size(153, 23);
-            textBox2.TabIndex = 4;
+            nameTextBox.Location = new Point(234, 127);
+            nameTextBox.Name = "nameTextBox";
+            nameTextBox.Size = new Size(153, 23);
+            nameTextBox.TabIndex = 4;
             // 
             // inventoryLabel
             // 
@@ -202,6 +204,7 @@
             saveButton.TabIndex = 15;
             saveButton.Text = "Save";
             saveButton.UseVisualStyleBackColor = true;
+            saveButton.Click += saveButton_Click;
             // 
             // cancelButton
             // 
@@ -211,6 +214,7 @@
             cancelButton.TabIndex = 16;
             cancelButton.Text = "Cancel";
             cancelButton.UseVisualStyleBackColor = true;
+            cancelButton.Click += cancelButton_Click;
             // 
             // AddModifyPartScreen
             // 
@@ -230,7 +234,7 @@
             Controls.Add(inventoryLabel);
             Controls.Add(inventoryTextBox);
             Controls.Add(nameLabel);
-            Controls.Add(textBox2);
+            Controls.Add(nameTextBox);
             Controls.Add(idLabel);
             Controls.Add(idTextBox);
             Controls.Add(outsourcedRadioButton);
@@ -252,7 +256,7 @@
         private TextBox idTextBox;
         private Label idLabel;
         private Label nameLabel;
-        private TextBox textBox2;
+        private TextBox nameTextBox;
         private Label inventoryLabel;
         private TextBox inventoryTextBox;
         private Label priceCostLabel;
diff --git a/C968Project/Views/AddModifyPartScreen.cs b/C968Project/Views/AddModifyPartScreen.cs
index 3c36dac..e909937 100644
--- a/C968Project/Views/AddModifyPartScreen.cs
+++ b/C968Project/Views/AddModifyPartScreen.cs
@@ -12,9 +12,163 @@ namespace C968Project.Views
 {
     public partial class AddModifyPartScreen : Form
     {
-        public AddModifyPartScreen()
+
+        private ScreenOption _screenOption;
+        private Part? _selectedPart = null;
+        private Mode _mode = Mode.INHOUSE;
+
+        public AddModifyPartScreen(ScreenOption screenOption, Part? part = null)
         {
             InitializeComponent();
+
+            _screenOption = screenOption;
+            _selectedPart = part;
+
+            if (screenOption == ScreenOption.ADD)
+            {
+                screenLabel.Text = "Add Part";
+                ChangeMode(Mode.INHOUSE);
+            }
+            else if (screenOption == ScreenOption.MODIFY)
+            {
+                screenLabel.Text = "Modify Part";
+                PopulatePartData(_selectedPart);
+            }
+        }
+
+        private void PopulatePartData(Part part)
+        {
+            idTextBox.Text = part.PartID.ToString();
+            nameTextBox.Text = part.Name;
+            inventoryTextBox.Text = part.InStock.ToString();
+            priceCostTextBox.Text = part.Price.ToString();
+            maxTextBox.Text = part.Max.ToString();
+            minTextBox.Text = part.Min.ToString();
+
+            if (part is Outsourced op)
+            {
+                ChangeMode(Mode.OUTSOURCED);
+                machineCompanyTextBox.Text = op.CompanyName;
+            }
+
+            if (part is Inhouse ip)
+            {
+                ChangeMode(Mode.INHOUSE);
+                machineCompanyTextBox.Text = ip.MachineID.ToString();
+            }
+
+        }
+
+        private void ModifyPart()
+        {
+            int partIndex;
+            if (_selectedPart != null && Program.Inventory.Parts.Contains(_selectedPart))
+            {
+                partIndex = Program.Inventory.Parts.IndexOf(_selectedPart);
+            }
+            else
+            {
+                MessageBox.Show("Error modifying part: Could not find part index", "Error", MessageBoxButtons.OK);
+                return;
+            }
+
+            var part = Program.Inventory.Parts[partIndex];
+            var partId = part.PartID;
+            Program.Inventory.Parts[partIndex] = CreatePart(partId);
+        }
+
+        private void AddPart()
+        {
+            int newId = Program.PartIdCounter;
+            Program.PartIdCounter++;
+
+            Program.Inventory.AddPart(CreatePart(newId));
+        }
+
+        private Part CreatePart(int partId)
+        {
+            Part part;
+
+            if (_mode is Mode.INHOUSE)
+            {
+                var inhouse = new Inhouse();
+                inhouse.MachineID = int.Parse(machineCompanyTextBox.Text);
+                part = inhouse;
+            }
+            else if (_mode is Mode.OUTSOURCED)
+            {
+                var outsourced = new Outsourced();
+                outsourced.CompanyName = machineCompanyTextBox.Text;
+                part = outsourced;
+            }
+            else
+            {
+                throw new InvalidOperationException("No part mode selected somehow");
+            }
+
+            part.PartID = partId;
+            part.Name = nameTextBox.Text;
+            part.InStock = int.Parse(inventoryTextBox.Text);
+            part.Price = float.Parse(priceCostTextBox.Text);
+            part.Max = int.Parse(maxTextBox.Text);
+            part.Min = int.Parse(minTextBox.Text);
+
+            return part;
+        }
+
+
+
+        private void saveButton_Click(object sender, EventArgs e)
+        {
+            if (_screenOption is ScreenOption.ADD)
+            {
+                AddPart();
+            }
+
+            if (_screenOption is ScreenOption.MODIFY)
+            {
+                ModifyPart();
+            }
+
+            Close();
+        }
+
+        private void cancelButton_Click(object sender, EventArgs e)
+        {
+            Close();
+        }
+
+        private void inHouseRadioButton_Click(object sender, EventArgs e)
+        {
+            ChangeMode(Mode.INHOUSE);
+        }
+
+        private void outsourcedRadioButton_Click(object sender, EventArgs e)
+        {
+            ChangeMode(Mode.OUTSOURCED);
+        }
+
+        private void ChangeMode(Mode mode)
+        {
+            _mode = mode;
+            if (mode is Mode.INHOUSE)
+            {
+                outsourcedRadioButton.Checked = false;
+                inHouseRadioButton.Checked = true;
+                machineCompanyLabel.Text = "Machine ID";
+            }
+            if (mode is Mode.OUTSOURCED)
+            {
+                inHouseRadioButton.Checked = false;
+                outsourcedRadioButton.Checked = true;
+                machineCompanyLabel.Text = "Company Name";
+            }
+        }
+
+        enum Mode
+        {
+            INHOUSE,
+            OUTSOURCED
         }
     }
 }
diff --git a/C968Project/Views/MainScreen.Designer.cs b/C968Project/Views/MainScreen.Designer.cs
index 0f9e006..7d0aea4 100644
--- a/C968Project/Views/MainScreen.Designer.cs
+++ b/C968Project/Views/MainScreen.Designer.cs
@@ -32,6 +32,7 @@ partial class MainScreen
     private void InitializeComponent()
     {
         panel1 = new Panel();
+        exitButton = new Button();
         productsDeleteButton = new Button();
         productsModifyButton = new Button();
         productsAddButton = new Button();
@@ -47,7 +48,6 @@ partial class MainScreen
         label2 = new Label();
         mainScreenLabel = new Label();
         partsDataGridView = new DataGridView();
-        exitButton = new Button();
         panel1.SuspendLayout();
         ((ISupportInitialize)productsDataGridView).BeginInit();
         ((ISupportInitialize)partsDataGridView).BeginInit();
@@ -80,6 +80,17 @@ partial class MainScreen
         panel1.Size = new Size(929, 450);
         panel1.TabIndex = 0;
         // 
+        // exitButton
+        // 
+        exitButton.Anchor = AnchorStyles.Bottom | AnchorStyles.Right;
+        exitButton.Location = new Point(842, 415);
+        exitButton.Name = "exitButton";
+        exitButton.Size = new Size(75, 23);
+        exitButton.TabIndex = 16;
+        exitButton.Text = "Exit";
+        exitButton.UseVisualStyleBackColor = true;
+        exitButton.Click += exitButton_Click;
+        // 
         // productsDeleteButton
         // 
         productsDeleteButton.Anchor = AnchorStyles.Right;
@@ -89,6 +100,7 @@ partial class MainScreen
         productsDeleteButton.TabIndex = 15;
         productsDeleteButton.Text = "Delete";
         productsDeleteButton.UseVisualStyleBackColor = true;
+        productsDeleteButton.Click += productsDeleteButton_Click;
         // 
         // productsModifyButton
         // 
@@ -99,6 +111,7 @@ partial class MainScreen
         productsModifyButton.TabIndex = 14;
         productsModifyButton.Text = "Modify";
         productsModifyButton.UseVisualStyleBackColor = true;
+        productsModifyButton.Click += productsModifyButton_Click;
         // 
         // productsAddButton
         // 
@@ -109,6 +122,7 @@ partial class MainScreen
         productsAddButton.TabIndex = 13;
         productsAddButton.Text = "Add";
         productsAddButton.UseVisualStyleBackColor = true;
+        productsAddButton.Click += productsAddButton_Click;
         // 
         // productsSearchButton
         // 
@@ -120,6 +134,7 @@ partial class MainScreen
         productsSearchButton.Text = "Search";
         productsSearchButton.TextImageRelation = TextImageRelation.ImageAboveText;
         productsSearchButton.UseVisualStyleBackColor = true;
+        productsSearchButton.Click += productsSearchButton_Click;
         // 
         // productsSearchTextBox
         // 
@@ -157,6 +172,7 @@ partial class MainScreen
         partsDeleteButton.TabIndex = 8;
         partsDeleteButton.Text = "Delete";
         partsDeleteButton.UseVisualStyleBackColor = true;
+        partsDeleteButton.Click += partsDeleteButton_Click;
         // 
         // partsModifyButton
         // 
@@ -167,6 +183,7 @@ partial class MainScreen
         partsModifyButton.TabIndex = 7;
         partsModifyButton.Text = "Modify";
         partsModifyButton.UseVisualStyleBackColor = true;
+        partsModifyButton.Click += partsModifyButton_Click;
         // 
         // partsAddButton
         // 
@@ -177,6 +194,7 @@ partial class MainScreen
         partsAddButton.TabIndex = 6;
         partsAddButton.Text = "Add";
         partsAddButton.UseVisualStyleBackColor = true;
+        partsAddButton.Click += partsAddButton_Click;
         // 
         // partsSearchButton
         // 
@@ -188,6 +206,7 @@ partial class MainScreen
         partsSearchButton.Text = "Search";
         partsSearchButton.TextImageRelation = TextImageRelation.ImageAboveText;
         partsSearchButton.UseVisualStyleBackColor = true;
+        partsSearchButton.Click += partsSearchButton_Click;
         // 
         // partsSearchTextBox
         // 
@@ -225,16 +244,6 @@ partial class MainScreen
         partsDataGridView.Size = new Size(440, 162);
         partsDataGridView.TabIndex = 0;
         // 
-        // exitButton
-        // 
-        exitButton.Anchor = AnchorStyles.Bottom | AnchorStyles.Right;
-        exitButton.Location = new Point(842, 415);
-        exitButton.Name = "exitButton";
-        exitButton.Size = new Size(75, 23);
-        exitButton.TabIndex = 16;
-        exitButton.Text = "Exit";
-        exitButton.UseVisualStyleBackColor = true;
-        // 
         // MainScreen
         // 
         AutoScaleDimensions = new SizeF(7F, 15F);
diff --git a/C968Project/Views/MainScreen.cs b/C968Project/Views/MainScreen.cs
index 8ca5f03..afc8503 100644
--- a/C968Project/Views/MainScreen.cs
+++ b/C968Project/Views/MainScreen.cs
@@ -9,4 +9,58 @@ public partial class MainScreen : Form
         productsDataGridView.DataSource = Program.Inventory.Products;
         partsDataGridView.DataSource = Program.Inventory.Parts;
     }
+
+    private void exitButton_Click(object sender, EventArgs e)
+    {
+        Application.Exit();
+    }
+
+    // --- Parts
+    private void partsAddButton_Click(object sender, EventArgs e)
+    {
+        AddModifyPartScreen partScreen = new AddModifyPartScreen(ScreenOption.ADD);
+        partScreen.Show();
+    }
+
+    private void partsModifyButton_Click(object sender, EventArgs e)
+    {
+        Part part = Program.Inventory.LookupPart(partsDataGridView.CurrentCell.RowIndex);
+        if (part is null) return;
+        AddModifyPartScreen partScreen = new AddModifyPartScreen(ScreenOption.MODIFY, part);
+        partScreen.Show();
+    }
+
+    private void partsDeleteButton_Click(object sender, EventArgs e)
+    {
+        Part part = Program.Inventory.LookupPart(partsDataGridView.CurrentCell.RowIndex);
+        Program.Inventory.DeletePart(part);
+    }
+
+    private void partsSearchButton_Click(object sender, EventArgs e)
+    {
+        // TODO: Search functionality
+    }
+
+    // --- Products
+    private void productsAddButton_Click(object sender, EventArgs e)
+    {
+        AddModifyProductScreen productScreen = new AddModifyProductScreen();
+        productScreen.Show();
+    }
+
+    private void productsModifyButton_Click(object sender, EventArgs e)
+    {
+        AddModifyProductScreen productScreen = new AddModifyProductScreen();
+        productScreen.Show();
+    }
+
+    private void productsDeleteButton_Click(object sender, EventArgs e)
+    {
+
+    }
+
+    private void productsSearchButton_Click(object sender, EventArgs e)
+    {
+        // TODO: Search functionality
+    }
 }
\ No newline at end of file