MAIL HELP!!!!!!!!!!!!!!!!!!!!!!

I install panther server last night and everything work perfect but I cant get mail to work and have a hard time following apples mail setup PDF. Can some one give me a quick overview of how to setup dns and mail. I have a DNS server pointing a MX recored to my IP address and a Linksys NAT router between me and the internet. The ports are all forwared and it works fine with a M$ exchange server. Help Please.