Army setup mostly refers to spell scripting. There are some things to know about distributing your mages around so arrow fire doesn't take them all out, putting hot/cold/poisonous creatures where they won't kill anyone else, positioning units to maximize your chances that a "Hold And Attack Rear" will actually get all the way to the rear, etc., etc., but Dominions tries to be more strategic than tactical and most of the tricks you can play center on researching/casting the right spells and equipping the right magic items on the right commanders and sending them to the right places to do things your opponent isn't expecting.
A couple of links that may or may not be useful:
Art of Placement
http://strategywiki.org/wiki/Dominio...ctical_Battles
-Max
Edit: fixed pathological link which was messing up page formatting.
Re: Newbish question
Threaded Mode