Can you explain who the Power 5 are, and what Division 0 would mean? And would Division 0 be inside or outside the NCAA? I don't get the implication of them all

Can you explain who the Power 5 are, and what Division 0 would mean? And would Division 0 be inside or outside the NCAA? I don't get the implication of them all leaving the NCAA to create their own organization is, because I don't know the players in this 'game'. EDIT: Answered in a jedberg reply elsewhere in this thread.