please help me figure out how this site works

Well, it is highly suggested that you begin with the "Help" in red at the top-right of the page.

This site is thankfully, unlike dozens of others, rather simple and user-friendly.  It is also very light on the bandwidth relative to the nonsense you will find elsewhere.

The first thing to do so (after reading the help) is head to the Wanted - Players section, and find a game that interests you.  There are tons of games, ranging from system-heavy to systemless - and in all genres.

Hang out in the community chat room, and you'll get to know the fun games and personalities that are out there.

Note also that the Help will try to show you the part relevant to the page you are on.  The forums have specific rules, conveniently in a section at the top.  And welcome!  You have much fun in store!

Figure out what kind of game(s) in which you want to play, Dungeons and Dragons, World of Darkness, free form, whatever.

Then go meandering through the "Wanted - Players" forum at link to another game where there are many many games actively seeking players.  Note: just because the ad is there doesn't mean the game is still looking for players -- look above the top post and there will be a little box there telling you whether or not the game is still looking for new players.  Under the thread will be other games that the GM runs, if any.

When you're ready to run a game, you can either start your own or head on over to "Wanted GMs" atlink to another game

For anybody looking to run a game, Wanted - GMs is probably the last place they should be going, as it's mostly intended for players who are looking for a game to join.

And even if they plan to find a co-GM for their own game, they would still need to set up that game before posting in the forum.

The list of game-related forums, and who should be starting threads in them:

Wanted - Players:                 GMs looking for players.  link to another game
Wanted - GMs:                     Players looking for games to join.  GMs looking for co-GMs for existing games.  link to another game
Game Proposals, Input and Advice: Potential GMs wanting to check for interest in a game before starting it.  link to another game

I always thought Wanted: GMs was a place where players who wanted a GM would post an ad, rather than looking for games to join.  *shrug*  As I pretty much never GM games, I've never worried about it.

In reply to facemaker329 (msg # 6):

Players can't post there just looking for a GM, that GM has to come with a game.  So "looking for GM" and "Looking for game" amount to pretty much the same thing.

Players can't post in "Wanted - GM" when there isn't yet a game and they want to find someone to act as GM to start the game?

Yes, players can.  But your suggestion was to post there if they want to start their own game.

GMs can't start a thread in Wanted - GMs unless they already have a game, and are looking for a co-GM.

Ah, I see where the confusion came from.  I never said to post there, I said to head over there.

I meant people should head over there, read the threads, find one that interests them. :)