You need to mark a bracket match as a Forfeit:

Go to Menu > Manage > Schedule/Charts > Charts (Bracket/RRB) or Calendar.

Find the match, Open the scoresheet**, click on the Option button (found inside the scoresheet).

Click on Forfeit.

Give the Trophy to the winner.

Finish the match.

This will automatically advance the winner and make the forfeit player or team the loser.

This is better than simply marking the match as Winner and forfeit player the loser. This helps the next match know that the previous match was a Forfeit. Therefor, the player may not show up for his second match either.

*Open the scoresheet in Calendar:

Select the match and click on a button called Score at the top.

**Open the scoresheet on the bracket:

Click in the middle of the match, an option button appears, choose Edit Score.