I can see you are a real nOOb.
Anyway, firstly welcome aboard to PHP.
Databases
You should be able to have at least 30 tables in one database this is quite alot but if designed correctly shouldnt put too much load on a server
Tutorials
I can suggest one which is where i learnt from
http://spoono.com
They can teach you how to
Add, Edit, Delete and Select from a database which will help you build you Admin. Session Tutorials and some more advanced ones.
Hope taht helps to start off.