Here is a site with lots of good information for newbys.
http://www.trapperman.com/
You'd want to put your bait so that the critter would pass through the trap to get the bait.
Check out the muskrat cubby set. You want to think of the trap as a guard. Its guarding your bait.
You can use body gripping traps without bait by setting them in trails. there are a couple of examples at trapperman.
Check out "basic sets at the bottom of the page
good luck
just