I don't know if this is the 'textbook' AWIN config but it's how I do it. I'm in Fayetteville.
New System - "MOT" type system
select P25
Edit Name - make it AWIN or whatever you like
go to Edit Sys Option - set a Quick Key. Whatever's convenient and available - I have mine on "2".
back out of that and go to "Set Frequencies"
Go
http://www.radioreference.com/modules.php?name=RR&sid=3918 here and enter all the frequencies that are listed under a "Troop L" site
If you want to enter talkgroups, go for it; since there are so many TG's I just keep it in ID SEARCH to pick up all talkgroups.
Note that I don't know if the "program in every frequency in one system" is the proper way to do it - I think you're supposed to run "one system, one tower" but I notice no decreases in performance or response time.