Register with the host of the bracket pool you wish to join. You'll need to enter a username, password and e-mail. Pools can be found at every major sports website, at many newspapers' online sites or can be created by friends.
Type in a name for your bracket. Many sites allow you to enter more than one bracket.
Select your winners for game. To select a winner, pick the school you believe will win from the drop-down box in each section. Continue this process for the entire bracket. When you are finished, you will have selected the NCAA Tournament champion.
Guess a tiebreaking score. Include a score or margin of victory, depending on the bracket host, to break a potential tie.