How to compile added source code for UE

I added a few source code files inside UE. I put them inside "Epic Games\UE_4.27\Engine\Source"

How can I compile the newly-added files so that I can use them as nodes inside my BluePrint.

(The new node is an animation node. I placed the .cpp and .h files of the editor and runtime inside the proper folders. I want to use them inside the AnimGraph of the AnimBP.)

Normally you’d not modify the engine itself but put the files into your Project folder / Source.
To compile them open the project .sln or engine source in Visual Studio Community and click Build.