I don't how im supposed to restart the game and do it the bad way i beat it good like two months ago and now want to do it evil do i need to delete the save data.

You don't need to delete the save data. You press start and go to Save Data part and choose New Game there. I think thats where it is, I don't exactly remember.

Press Start, and you should see Start A New Game along with the save and load... I think, I'm doing this from memory.

I'll put it in later and check, but I'm quite sure the last posts are right. Just go to where you would go to save, and there should be a new game option.

Press Start and go to were you see save data. You should see the option there.

Also if you haven't played it on hard mode yet and want to, make sure you switch the difficulty BEFORE you start new game.