This should be in the Multiplayer section....
However things are much the same as in CFS rooms .... you join the games in much the same way and the rules are set by the host of the game. The more serious games may ask you to state your intentions and file flight plans, some may even have live ATC. It is curtious not to join a game at the end of the runway but at a gate or ramp in the start airport. This seldom happens in "The Zone" so it is best avoided. If you want to fly multiplayer either seriously or in a more relaxed fashion then I would suggest downloading FSHostSpy from chocolatesoftware ... this little gadget finds all the FSHost games and presents them along with their info ... you simply click on your game of choice and make a note of the IP. Copy that IP into ya multiplayer section and search for the session ... and join it ... There ya go Bobs ya aunt 

Theres plenty of other options depending on how seriously you want to take your civil flying ... Check out the multiplayer sections of the boards for more info and tips.

cheers
eno