Before you can play backgammon on GridGammon, you must log in to the server. Your Mac must be connected to the Internet, and you must have a GridGammon account to log in.
To log in, choose the Connect... menu item under the GridGammon menu, or you can click the Connect button in the Lobby window toolbar:
Connect
This will open the Connect window, which allows you to enter your user name and password. If you do not yet have a GridGammon account, you can click the New Account... button to connect to the GridGammon web site where you can create a new account.
If you are using GridGammon on your own Macintosh, you may want to check the "Remember Password" checkbox. GridGammon will store your password in the System Keychain for you, and when you connect the next time, will use this saved password so that you don't have to type it again.
To log out of GridGammon, choose Disconnect from the GridGammon menu, or click the Disconnect button in the Lobby window toolbar (the Connect button switches to the Disconnect button when you are logged in).