We'll stick with the MAIN War Games rules, since later versions were gimmicked up and defeated the point.
One big cage, over two rings that are next to each other (though usually there's a gap just big enough that you can stuff someone down.) The cage covers the permieter of the ring - it only extends to the aprons, not ringside like HITC.
There are two sides of wrestlers - either 4 or 5 people.
One person from each side starts in the cage, and they're fighting alone for the starting period (usually five minutes.) From a booking perspective, this is either two guys who have a mid-card issue, or your two best workers.
Near the end of the starting period, a coin toss is held to determine which side gets the next person in. This coin toss was won every time by the heels.
As soon as the starting period is over, the winning team sends in their second wrestler. From then on, the teams alternate sending in people every TWO minutes, till everyone's in the cage.
The match can NOT be won until everyone is in the cage.
Once everyone is in, the match can end by SURRENDER or SUBMISSION. I never really got the difference, but I presume submission is what you assume it is, and Surrender is like "No, no, don't slam the door on Flair's head, we give up!" - a non-submission end to the match.