How to route my toll free to asterisk server?

Hi everyone… I am very new to asterisk but I am very much interested in it. I am planning to start a callcentre. I want to route my toll free to my asterisk server.(When user calls to the tollfree I want to make it ring one of my extensions in my asterisk server) What should I do? Do I need any hardware??
thanks in advance…

For a starter, it is best to use a plain/vanilla asterisk with no GUI and read this Asterisk: The Future of Telephony, 2nd Edition e-book to learn how to configure/maintain/operate an Asterisk PBX system.