The Perfect Ten rules?

We got this for Christmas and tried to play last night, but couldn't get the rules at all. Are you only meant to play ten rounds? If you only score when you get all ten questions right...we played ten rounds and neither team scored. And if that's the only time you score, what is the purpose of marking how many questions were gotten correctly, as it seems to have no bearing on the game? And what's the deal with moving the free answer markers down on the board? Does that mean you always get that category free?