How to use macros defined in Tower Defense Sample?

Was there any way to find the blueprints or source code of the mechanic that handles creepwave spawn? I’m looking at all the blueprints I see and most of them don’t even have any scripts. I read the guide on this map and they apparently use macros which I don’t know how to use. Would I need to migrate three Blueprint Macros: spawn fast, spawn normal, and spawn heavy from this sample if I wanted to use them? Or could I call them myself in my own project? How do I look at the structure of these macros so I can learn how they work?

How would I go about doing this?

EDIT: found the source folder with all the c++ code, but I still can’t find the scripts folder, the location of which seems to be implied when you highlight over the blueprints in the content browser of the TD sample