well basically just install it, run it and you're ready to go. the first thing you might wanna do is create MX records in your DNS. i do recall you saying that you're with DynIP or someother group (can't recall)
if so then chances are you wouldn't need to set-up MX records anymore (then again, i really can't recall how DynIP worked)
as for the mail server side of things, to get a basic system running just configure the System tab.
Then go to the Accounts tab, hit CTRL-D (create a domain) and then CTRL-U (create a user)
you're set
