What Shold I do for new ABAP system from Basis administrators view?

I'm a basis administrator but with a little experience.

So I created new ABAP system(NW AS ABAP INNOVATION PACKAGE 7.51) to study.

However I don't know what basic preparations are for new system.

Please share your knowledges.

I'm trying to create new client and user but I'm often confused what is correct Procedure....