“First, you need to set up a special server target for UnrealBuildTool.” - And what does this mean and how should I do it ?
That mean you need create server.target.cs file with special code.
“Save it as Server.Target.cs next to the other target files and regenerate the project files.” - Where are the other target files ? Because I cant find them. I used only blueprints in my project with no c++ features added.
Add c++ feature. Create any c++ class, empty for example and UE4Editor create Source folder with needed code for you