If you want to play, then simply choose a game and press “join”. You can also create a new game yourself, enabling other players to join your game. Just click “new game” on an available table. You can also press the button “new game” next to the chat window. This way, a new game will be created automatically.
When you create a new game but people don’t join right away, you can choose to start a “singleplayer” game until other people join the table. As soon as other people join the table they get a message that the “multiplayer” game will start as soon as your game is finished. This way you can keep on playing while waiting for other people to join your table!