1: Install: Unreal Engine Source

Note: In the future, I will set up a Proper Unreal Engine Fork. As of now Installation of the Renderer is Manual.

Installing Unreal Engine Source

1. You will require a Source Build of Unreal Engine. Follow Instructions on the Following pages:
   https://www.unrealengine.com/en-US/ue-on-github
   https://dev.epicgames.com/documentation/en-us/unreal-engine/building-unreal-engine-from-source
   
2. After Gaining access, Download UE 5.2.1
   https://github.com/EpicGames/UnrealEngine/tree/5.2.1-release
3. Make a New directory and extract the source code
   I recommend making a directory in the Drive root to avoid hitting the Path Lenght Limit (eg. C:\UE-5-2-1).
   Please use a fast SSD drive otherwise the compilation may take large amounts of time (It took around 15 hours on my HDD).
   
4. Run Setup.bat, then GenerateProjectFiles.bat
   This will download dependencies and create the Visual Studio Solution file (.sln).
5. Open Visual Studio and load UE5.sln
   
6. In the Solution explorer, Right click "UE5" and hit Build
   Close all other applications to free up RAM, this will allow more processes and faster Compilation.
   Even on a Fast drive this will take a few hours.
   If you get "Error C4756 Overflow in Constant Arithmetic" after Compilation, you will have to apply fixes from the Next page.
7. When it Finishes, In the Solution Explorer right click the UE5 project and click "Debug->Start New Instance" to Run Unreal Engine
   
8. After Compilation, The Executable will be generated at Engine\Binaries\Win64\UnrealEditor.exe. You can create a Shortcut so you can Launch it from Desktop. You can Optionaly launch it to test if the Engine is working.
   

Tips for Beginners

1. If you decide to implement your own Modifications to Unreal, it is good practice to mark all locations you edited. For example I always add a comment using my name as a Keyword and optionaly what I changed. Later I can Search the Source code for "ADM8" to find and Track all modifications I have applied.

if (bIsAquaRay) //ADM8 Adds shaders from AquaRay.cpp
{
	if (!IsForwardShadingEnabled(ShaderPlatform))
	{
		ViewFamily.EngineShowFlags.SetAquaRay(true);
		for (const FViewInfo& View : Views)
		{
			AquaRayPrepareRayTracing(View, RayGenShaders);
		}
	}
}

2. Do not update any Packages. You will get warnings about packages with Vulnerabilities, but they are safe to ignore in this case as they dont affect the Engine. Using newer Packages will cause compilation errors as the Source Code is adapted only to packages it was originaly created with.
3. Some changes might trigger Recompilations of larger parts of the Engine. Be careful what you edit and be Patient.