Can't find GenerateProjectFiles

I’ve been trying to create in-app purchase, but im having no luck and was recommended to download SDKBOX. I installed it correctly it just wants me to run GenerateProjectFiles in my engine root, but i can not find it.

I think GenerateProjectFiles is only available in source built engine root folders. It has been a long time since I worked without a source built engine, but I think you can generate project files off of your .uproject file.