Action Rounds - An action round is a brief period of time - about two seconds - enough time for most characters to attempt a couple of actions. At the beginning of each round every character's used hit points become ready. Then the characters take turns trying to do various moves or combinations of moves until they all have no more ready hit points.
Turns - Any number of characters can try to act during a single turn. These actions occur simultaneously but they don't all start at exactly the same time, so it is important to decide which characters will decide how to act first.
Surprise - if a character uses stealth or some other trick they decide how to act first regardless of other factors.
Outreaching - Usually the character with the longest reach gets to decide how to act first. But if two characters are closer than half the reach of the longest character's weapon, then the closer character actually gets initiative (except for missile weapons which still get initiative when they have the most range.)
Also, if a character is outreached and not using a missile weapon or similar long range weapon, he can only attack his target's weapon and not the target, and then only when his target attacks him. The exeption is if when his target attacks the target's weapon's reach is shorter than the defender's (this character's) total reach.
Interfering - An action can be used to keep another action from succeeding. The roll for the success of this action is one roll against the success of the action being prevented. There can be several rolls against the success of one action. If any of these are successful the action fails. Interfering actions can't use more hit points than the action being interfered with.
Multiple Weapons - Each weapon a character uses simultaneously can be used once per turn.