How do I remove the battery from my 1999 pontiac montana minivan?

I know i have to remove the round bar and the wire connected to the relay box, as well as moving the relay box to get to the battery, but I can't figure out how I'm supposed to remove the negative cable. I don't see a bolt or anything, do I just pull it?How do I remove the battery from my 1999 pontiac montana minivan?the screw is in the middle. It should come off just like the positive did.