Game Name
Useful if you know the name of the specific game you are looking for.

Preferred Map
Click this box if you'd like to specify a preferred map. Once you've selected this check box you will be able to choose your favorite map from the list.

Preferred Game Type
Click this box if you'd like to specify a preferred game type (Territories, Capture The Flag, etc.). Once you've selected this check box you will be able to choose your favorite game type from the list.

Allies
Lets you specify games that allow allies or games that don't allow allies. For this and all of the below options you can also select a third option, "don't care"– saying you don't care will ignore this setting in the game search.

Unit Trading
Lets you specify games that allow unit trading or games that don't allow unit trading.

Enemy Visibility
Lets you specify games that allow enemy visibility or games that don't allow enemy visibility.

Teams
Lets you specify games that allow teams or games that don't allow teams.

When you join a game the buttons under the player list will change to:

Join Team
Highlight a player name and click this button to join that player’s team.

Lock/Unlock Team
Click Lock Team to prevent any other players from joining your team. The button will change to Unlock Team, which you can click if you change your mind later.

Boot From Team
Click on a player and use this button to remove him from your team.