configure TMG 2010 and Exchange 2010 for e-mail and content filtering.

Hi there!
i need to configure external mail on my exchange 2010 and cofig it with TMG2010 to use e-mail and content filtering and corporate mail.
we have TMG2010 installed with 2 NICs, edge transport on it, Exchange 2010, AD+DNS. all servers are running Windows Server 2008R2.
I'm new in TMG and Exchange so the question is > 
1. how to configure them (order and details), 
2. how to do a RIGHT config for DNS MX records, 
3. how to config e-mail filtering to deny sending of source codes from clients computers to outside.

Maybe it's not the right place in forum to put this questions, but i need some help and assistance on this. i've make a lot of research for "how to" or "step by step" but looks like everything is for advanced admins.

if i need to provide more details, please tell me.

thanks