New to asterisk

i am new to asterisk and i have got the project to setup asterisk ivr solution
in my company , i have already configure digium (TDM22B) i am able to make and recieve calls throiugh asterisk but do not know how to implement advance features like call waiting and voice mail please help

You will find a vaste amount of help at:

voip-info.org/tiki-index.php?page=Asterisk