There is an error when excute GenerateProjectFiles

I’m following the tutorial down below.
link text

I downloaded unreal engine source code on 4.12 engine folder and run setup.bat, and excuted GenerateProjectFiles.bat

But there is an error message, and I don’t know why

The message is :

UnrealBuildTool Exception: Error : A game project path was not specified, which is required when generating project

files using an installed build or passing -game on the command line

GenerateProjectfiles Error: UnrealBuildTool was unable to generate project files.

Please help me :frowning:

I think you need to create project from launcher first, then use the bat file