Coming back after a lengthy absence from PnP games and I am trying to get into Pathfinder, but i want to know why split Combat Maneuvers from regular attack roles?
What are the advantages of a Combat Maneuvers?
Yes as ernie said it is more used for things that aren't your regular attack but are still aggressive in nature such as grapple and the like. You can also use it when trying to do something not specifically outlined in the rules. That is my understanding of it anyway.
Most combat maneuvers are a standard action. You can check the rules on the PRD regarding this
<a href="http://paizo.com/pathfinderRPG/prd/combat.html" rel="nofollow">http://paizo.com/pathfinderRPG/prd/combat.html</a>