If you run out of time to make your move, you lose the game.
You do have some "vacation time" available to use, which pauses your games if you know you are going to be away from your computer for a while.
Go to My Home > Account > Online Chess Settings
Near the bottom there is an option to pause your games, and tells you how much vacation time you have available. Since you are a new member, you may not have very much.
You can also set up your games for 5, 7, 10, or 14 days per move.