Make the dev docs more betterer (#21467)

* Make the dev docs more betterer

* forestalled potential errors in select startup project

Author: stephen-hawley

.github/DEVELOPMENT.md

@@ -15,6 +15,19 @@ This page contains steps to build and run the .NET MAUI repository from source.
       - Follow [these steps](https://learn.microsoft.com/en-us/dotnet/maui/get-started/installation?view=net-maui-8.0&tabs=visual-studio-code), installing VS Code, MAUI extension, .NET8, Xcode, OpenJDK, and Android SDK
       - Install Mono from [Mono Project](https://www.mono-project.com)
       - For Xcode, you can install from the [App Store](https://apps.apple.com/us/app/xcode/id497799835?mt=12) or [Apple Developer portal](https://developer.apple.com/download/more/?name=Xcode)
+      - As of 26 March 2024, Xcode 15.3 is not yet supported. Check [this issue](https://github.com/dotnet/maui/issues/21057) for updates
+      - Edit your `.zprofile` file to ensure that the following environment variables are set/modified (you may need to adjust the version of OpenJDK):
+      ```shell
+      export JAVA_HOME=/Library/Java/JavaVirtualMachines/microsoft-11.jdk/Contents/Home
+      export ANDROID_HOME=~/Library/Android/sdk
+      export ANDROID_SDK_ROOT=~/Library/Android/sdk
+      export PATH="$PATH:~/.dotnet/tools"
+      export PATH="$PATH:$ANDROID_HOME/platform-tools"
+      export PATH="$PATH:$ANDROID_HOME/tools"
+      export PATH="$PATH:$ANDROID_HOME/tools/bin"
+      export PATH="$PATH:$ANDROID_HOME/tools/emulator" 
+      ```
+      - In VSCode do `command--shift-P` then type `code path` and select the option `Shell Command: Install 'code' in PATH`
 
 ## Building the Build Tasks
 Before opening the solution in Visual Studio / VS Code you **MUST** build the build tasks.
@@ -143,6 +156,21 @@ These are tests that will not run on a device. This is useful for testing device
 │   │   ├── Essentials.UnitTests
 ```
 
+### Reproducing an Issue/Debugging .NET MAUI Code
+Open the .NET MAUI workspace in VSCode.
+In VSCode, select the device that you will be testing on. Using the command palette (ctrl-shift-P/command-shift-P) type `pick device` and
+you will be presented with a set of choices for your target device (Android, iOS, etc). Select one.
+There is a sample project in `src/Controls/samples/Controls.Sample.Sandbox`. This is an empty project
+into which you can add your code to reproduce an issue and also set breakpoints in .NET MAUI source code.
+Let VSCode know this is the project you want to select by going to the command palette (ctrl-shift-P/command-shift-P)
+and typing `pick startup` and select ".NET MAUI: Pick Startup Project" and select the Sandbox project.
+
+ Before using the command palette for the first time, you may have to wait a minute
+for intellisense and other tasks to complete before using the command palette. If the project hasn't
+'settled' yet, you will see an error "Pick Startup Project has resulted in an error."
+
+*Note:* When you are committing your PR, do not include your changes to the Sandbox project.
+
 ### Integration Tests
 
 The Integration test project under `src/TestUtils/src/Microsoft.Maui.IntegrationTests` contains tests which build and/or run MAUI templates or other projects.