i want to learn HR ABAP Pls help

Hi all

I want to learn hr abap but sites like sap-img and sap.com and atomhr doesnt help to start .Once we know basic concepts then we can continue But to kicj off its difficult.Tried all main sites but no use

Pls help if you have any good material.

is it called HR abap or SAP hr?

is info types starting with 0001 or is it with p0002???

which is the one?

George