[Dragokas]

If you want to learn, open:

https://wiki.alliedmods.net/Adding_Admins_(SourceMod)
https://wiki.alliedmods.net/Adding_Groups_(SourceMod)
https://wiki.alliedmods.net/Checking...eMod_Scripting)
https://wiki.alliedmods.net/Overridi...ess_(SourceMod)

read, think, use.
Then, open source code of SourceMod basic plugins (e.g. /admin-flatfile/) and study.

I would begin with learning of new syntax and basic things first.

New permissions on admin can be granted by modifying its AdminId and re-assigning with SetUserAdmin().