To record the 3rd set tiebreak you will first input a 1 in the 3rd set box for the winner of the set and a 0 for the loser of the set. Once you do that a new set of boxes will populate.
In the new box that populates you will enter the final tiebreak result. After you click out of the score box the tiebreaker score will appear properly. Just select Save & Next or Save & Exit to record the result.