diff --git a/.github/CONTRIBUTING.md b/.github/CONTRIBUTING.md
index 0e9c9d3..bb37818 100644
--- a/.github/CONTRIBUTING.md
+++ b/.github/CONTRIBUTING.md
@@ -48,7 +48,7 @@ You can launch the prerelease version of Win11Debloat by running this command:
 2. Enable script execution if necessary:
 
    ```powershell
-   Set-ExecutionPolicy Unrestricted -Scope Process -Force
+   Set-ExecutionPolicy Bypass -Scope Process -Force
    ```
 
 3. Navigate to your Win11Debloat directory
@@ -60,38 +60,74 @@ You can launch the prerelease version of Win11Debloat by running this command:
 
 ### Running Automated Tests
 
-The automated test cases use Pester 5 and do not modify the registry or other
-system state. The optional bootstrap step installs Pester for your user account
-when needed. To run the complete suite:
+The automated tests use Pester 5 and are found in the Tests/ directory. They cover registry operations, app removal, CLI/GUI logic, and config handling. Some Windows behavior is mocked so the tests can run safely, but they do not replace manual testing on a Windows test environment.
+
+The bootstrap option can be used to automatically install Pester on your machine and run the full suite of tests:
 
 ```powershell
 .\Scripts\Run-Tests.ps1 -Bootstrap
 ```
 
-After the initial setup, run the suite with:
+After the initial setup, you can simply run the full suite with:
 
 ```powershell
 .\Scripts\Run-Tests.ps1
 ```
 
-GitHub Actions runs the same test command with Windows PowerShell 5.1 for pull
-requests and pushes to `master`.
+For a focused test run during development, you can also call Pester directly:
 
-## Implementation Guidelines
+```powershell
+Invoke-Pester -Path .\Tests\Invoke-Changes.Tests.ps1 -Output Detailed
+```
+
+GitHub Actions runs the same suite with Windows
+PowerShell 5.1 for pull requests and pushes to `master`.
+
+## Architecture & Design
+
+Win11Debloat is a PowerShell script with a WPF (Windows Presentation Foundation) based GUI and command-line interface. The CLI provides an alternative to the GUI, allowing most features and app-removal functionality to be invoked directly through command-line parameters. The project uses a data-driven architecture, separating feature and application definitions from the logic that applies them.
+
+### Entry Points
+
+`Win11Debloat.ps1` is the main entry point and can be launched directly or through one of the provided launchers:
+
+* `Run.bat` launches a locally downloaded copy of `Win11Debloat.ps1`.
+* `Get.ps1` downloads Win11Debloat and launches `Win11Debloat.ps1`.
+
+Both `Get.ps1` and `Win11Debloat.ps1` support [command-line parameters](https://github.com/Raphire/Win11Debloat/wiki/Command-Line-Interface), allowing Win11Debloat to be configured and run without using the GUI.
+
+### High-Level Architecture
+
+`Win11Debloat.ps1` loads the configuration and shared functions, then routes execution through either the WPF GUI or CLI. Both interfaces use the same underlying feature and app-removal engine.
+
+```mermaid
+flowchart TB
+    Main[Win11Debloat.ps1] --> GUI[WPF GUI]
+    Main --> CLI[CLI]
+
+    Config["Config Files (JSON)"] --> GUI
+    Config --> CLI
+
+    GUI --> Changes[Apply Selected Changes]
+    CLI --> Changes
+    Config --> Changes
+
+    Changes --> Regfiles[Regfiles]
+    Changes --> Tools[Appx / WinGet]
+```
 
 ### Project Structure
 
-Understanding the project structure is essential for contributing effectively:
-
 ```text
 Win11Debloat/
 ├── Win11Debloat.ps1             # Main PowerShell script
-├── Run.bat                      # Batch launcher for the quick launch method
+├── Run.bat                      # Local launcher
 ├── Scripts/                     # Additional PowerShell scripts and functions
-│   ├── Get.ps1                  # Script used for the quick launch method to automatically download and run Win11debloat
+│   ├── Get.ps1                  # Download-and-launch script
+│   ├── Run-Tests.ps1            # Pester test runner (optionally bootstraps Pester)
 │   ├── AppRemoval/              # App package removal logic
 │   ├── CLI/                     # Command-line interface helpers
-│   ├── Features/                # Feature apply/undo logic (e.g. Invoke-Changes.ps1, Replace-StartMenu.ps1)
+│   ├── Features/                # Feature apply, undo, backup, and restore logic
 │   ├── FileIO/                  # File input/output helpers
 │   ├── GUI/                     # GUI window definitions and logic
 │   ├── Helpers/                 # Shared helper functions
@@ -104,16 +140,19 @@ Win11Debloat/
 ├── Regfiles/                    # Registry files for all features
 │   ├── Undo/                    # Registry files for reverting features
 │   └── Sysprep/                 # Registry files for Sysprep mode
-├── Schemas/                     # XAML Schemas for GUI elements
+├── Schemas/                     # XAML views and shared GUI resources
 ├── Assets/                      # Static assets (icons, start menu templates)
+├── Tests/                       # Pester tests for script and XAML contracts
 ├── Backups/                     # Registry backups (generated during use)
 └── Logs/                        # Script logs (generated during use)
 ```
 
+## Implementation Guidelines
+
 ### Best Practices
 
 1. **Test Thoroughly**: Always test your changes on a Windows test environment before submitting. This includes undoing tweaks and running script as another user and in Sysprep mode.
-2. **Document Changes**: Update the `README.md` and other relevant documentation. Wiki documentation will be generated/updated based on the `Features.json` and `Apps.json` files.
+2. **Document Changes**: Update the `README.md`, wiki, and other relevant documentation.
 3. **Follow Existing Patterns**: Look at existing implementations for guidance.
 4. **Use Clear Naming**: Choose descriptive names for features, IDs, and registry files.
 5. **Minimal Changes**: Registry files should only modify what's necessary. Avoid using policies where possible.
@@ -137,7 +176,7 @@ Avoid these common mistakes when contributing:
 
 1. **Forgetting Get.ps1**: When adding a new command-line parameter, contributors often remember to add it to `Win11Debloat.ps1` but forget to add the same parameter to `Scripts/Get.ps1`. Both files **must** have matching parameters.
 
-2. **Missing Registry Files**: Always create an `Undo` registry file for reversibility, aswell as a `Sysprep` registry file for applying changes to other users and Sysprep mode.
+2. **Missing Registry Files**: For registry-backed features, create an `Undo` registry file for reversibility and a `Sysprep` registry file for applying changes to other users and Sysprep mode.
 
 3. **Incorrect Registry Hives for Sysprep**: Sysprep registry files are meant to apply changes to a different user. Registry keys in the `HKEY_CURRENT_USER` hive must use `hkey_users\default` instead. Ensure you update **all** registry keys in the file.
 
@@ -165,12 +204,14 @@ Avoid these common mistakes when contributing:
 
 To add a new app that can be removed via Win11Debloat:
 
-1. **Find the AppId**: To find the correct AppId for an app:
+1. **Find the AppId**: For an Appx app, find the package name with:
 
    ```powershell
    Get-AppxPackage | Select-Object Name, PackageFullName
    ```
 
+   For a WinGet app, use `winget list` and use its `Id` value.
+
 2. **Edit `Config/Apps.json`**: Add a new entry to the `"Apps"` array:
 
    ```json
@@ -187,7 +228,9 @@ To add a new app that can be removed via Win11Debloat:
    **Field Descriptions**:
 
    - `FriendlyName`: Display name shown in the GUI.
-   - `AppId`: The `AppPackageIdentifier` from `Get-AppxPackage` or the `Id` from `winget list`, depending on removal method.
+   - `AppId`: The package name from `Get-AppxPackage` or the `Id` from
+     `winget list`, depending on removal method. Use an array when one app
+     requires multiple identifiers.
    - `Description`: Brief description of the app shown in the GUI.
    - `SelectedByDefault`: Set to `true` only for apps that are largely considered bloatware, otherwise set to `false`.
    - `Recommendation`: Indicates how strongly the app is recommended for removal. One of:
@@ -201,7 +244,6 @@ To add a new app that can be removed via Win11Debloat:
 3. **Follow the Guidelines**:
 
    - Use clear, user-friendly names for `FriendlyName`
-   - Set `SelectedByDefault` to `true` only for apps that are largely considered bloatware, otherwise set to `false`
    - Provide a concise description explaining what the app does
 
 ### Adding a New Feature
@@ -289,6 +331,10 @@ Add a corresponding parameter to both `Win11Debloat.ps1` AND `Scripts/Get.ps1`,
 [switch]$YourFeatureId,
 ```
 
+#### 4. Add or Update Tests
+
+Add or update Pester coverage for the new behavior, then run the full suite.
+
 ### Adding a Feature to the Default Preset
 
 > [!IMPORTANT]
@@ -354,17 +400,23 @@ To add a new category for organizing features:
 
   ```json
   {
+    "CategoryId": "YourCategoryId",
     "Name": "Your Category Name",
-    "Icon": "&#xE#### ;"
+    "Icon": "&#xE####;"
   }
   ```
 
+  Use a stable, unlocalized `CategoryId`; it is used for category preset
+  mapping.
+
 > [!TIP]
 > Use [Segoe Fluent Icon Assets](https://learn.microsoft.com/en-us/windows/apps/design/iconography/segoe-fluent-icons-font) for icon codes.
 
 ### Adding UI Groups
 
-UI Groups allow features to be grouped together in the GUI with a combobox (dropdown) selection:
+UI Groups allow features to be grouped together in the GUI with a combobox
+(dropdown) selection. Add the group to the top-level `"UiGroups"` array in
+`Config/Features.json` and use a unique `GroupId`:
 
 ```json
 {
@@ -386,6 +438,11 @@ UI Groups allow features to be grouped together in the GUI with a combobox (drop
 }
 ```
 
+Define the referenced features before adding a group. Each `FeatureId` in a
+group's `Values` list must already be defined in `Features.json`. Features
+referenced by a group are shown through that group rather than as standalone
+controls.
+
 ## Submitting a Pull Request
 
 1. **Commit your changes** with clear, descriptive commit messages:
@@ -406,7 +463,7 @@ UI Groups allow features to be grouped together in the GUI with a combobox (drop
    - Go to the original Win11Debloat repository
    - Click "New Pull Request"
    - Select your fork and branch
-   - Provide a clear description of your changes, include references to the registry keys used
+   - Provide a clear description of your changes. For registry changes, include the registry keys used
    - Reference any related issues
 
 4. **Respond to feedback**: Be prepared to make adjustments based on code review feedback.