The function key is the F5 key, which is located above the regular numbers, kind of between 6 and 7. That refreshes you without you having to log out and log back in. Major time saver.
After that, just do what swimmingneno said, enter the game name (watch out on this, because they sometimes don't use the same name AND some nasty folks out there like to make their room name similar to the host game to confuse people), then keep clicking search until it pops up. Click on it and hopefully you've made the queue.
If you can't be there right when a room opens, refresh, then keep trying to enter the room repeatedly. Click guest rooms, then the game room (it will always be the #1 position on popular rooms). Do this for about four minutes. If you are not in the queue within four minutes, refresh and start again. If you go any longer than four minutes and get into the queue, you are guaranteed to dc either while in queue or while in the room.
Works great for me, 99% of the time. Some days, nothing works, and you just sigh and go on!