You may want to give them some general idea of the philosophy behind it:
-Doing anything particularly useful,whether it's hitting someone, shooting someone, reading a scroll, drinking a potion, breaking someone's sword, or casting a spell is usually a standard action. Only one standard action per round.
-Doing something less immediately useful, such as moving from point a to point b, or standing up, or getting something ready (a potion from your backpack or a sword from a sheath), is generally a move equivalent action. You can take one of these per round, or two of them if you give up your standard action.
-If you ever get to attack more than once in a round, it's a full attack action, meaning no move action for you.
I think understanding this general idea helps avoid having to memorize a whole list of things you can and can't do. Sure, there are a few exceptions -- getting material components ready is a free action, for instance -- but knowing the basic philosophy means you won't have players trying to drink a potion and shoot someone in the same round.
Daniel