Im new sorry, set up github

best way to set up the projects
have my
script (GAS, VBA, shell …), and code (Cpp, assembly, java)

the product using on

so Gas just see GAS

I’m not sure, if I understand you correctly.

First of all, you should have knowledge about git in general to understand GitHub.
I can recommend you the official git book: Git - Book

After that, you can use the GitHub Learning Lab to get started with the basics. This should answer your questions: