what happens to the new buyer?

I am a beginner at this process. I've been doing some reading about the foreclosure process. Most of it makes sense to me, except what happens to the new "owner" (the person who placed the highest bid at the sheriff's sale) if the previous owners (who defaulted) have 1 year from the sheriff's sale to redeem their ownership? Does the new owner have to wait to move in?[/b]