If the Include Tie Breaker box is selected, your game will automatically include a Tie Breaker if 2 or more teams have a tie score at the end of a match. To select and unselect, simply click on the check box. When the box is empty, the option is not selected. When marked with an X, the option has been selected:
The default setting for Include Tie Breaker is 'checked', i.e., to include a Tie Breaker in the game.