It would be in the GM's guide, but the basic breakdown was this:
Brutes: Cannon fodder, pretty much you hit them and the drop (much like 4e's minions having only 1 hit point). You could even call raises on your attack roll to hit multiple brutes at once (known as playing Whack-a-Brute) to mimic the cinematic action of the dashing hero dispatching a pack of nameless thugs in a rapid flurry of swordplay.
Henchmen: A step up from brutes, in that they could keeping fighting until they took a Dramatic Wound as a result of failing a Wounds check.
Villains: The top of the bad guy pyramid, in that they operated the same way as the PCs did in terms of Flesh Wounds and Dramatic Wounds.