How to Play: Joining a Casual Game
Index -> Interface -> Casual Games Lobby -> Joining Casual Games
Player-created games show up as Game Medallions in the main area of the Casual Games Lobby. When a game is awaiting players, the number showing players ready will be something like "1/2" or "2/4" indicating there is room for more.
To join a game, simply click the Play button on a Game Medallion that has at least one open slot. This will bring up the Join Game dialog box.

Select which fleet you'd like to use for the game. If you click the Browse Fleets button, you can choose any fleet file saved on your computer. If you use the dropdown button, you can quickly select one of your most recently used fleets. If you have any Online Fleets saved, these are also accessed by the dropdown button. The Fleet Selection defaults to the last fleet you used.
Once you have made your selection, click the Join button.