This article describes all Prefer Off Bid Options. Your configuration will vary depending on what Reserve Module you have.
All or Nothing
All or Nothing tells the N-PBS Scheduler that if you cannot have all of the days or dates off, you do not want any of the days or dates off. This tells the N-PBS Scheduler that they should continue to process your bid group without considering this preference.
Else Start Next Bid Group
Else Start Next Bid Group tells the N-PBS Scheduler that if you cannot have all of the days or dates off, you want the Scheduler to move to the next bid group (either Pairings or Reserve, depending on your bid) and begin processing it.