BYU wins CCG but based on the CFP hosing is the 5th conference and therfore has to play a first round game.

BYU wins this game and feeds into the Rose Bowl.

Then BYU wins the Rose Bowl to advance.

BYU becomes the first Holy War participant to win a Rose Bowl...

🙂

Note it seems to be understood that if the B12 is a top 4 conf their champ will go to the Fiesta Bowl so being the 5th conf is likely the only thing that allows this scenario to happen.