ranking teams 1-25. At the end of the season, the top 4 ranked teams will be assigned to the two semi-final games. The other bowls will be filled first according to the terms of the contract each bowl has with the various conferences, and then once all that is settled, the remaining at-large bowl slots (as few as one slot, as many as five I think, depending on the year and conference champion situation) will be filled with the highest-ranked remaining teams taking the available slots.