One of those straps is for the back seat. When it's folded up, there's a post on the seat bottom. It's normally in the latch when the seat is down. Wrap the strap around the roll bar, stick one end through the loop on the other end, then put the free end loop over the post on the seat. It keeps the seat from tipping/falling back when you pull out from a stop.
I think the other strap is for the windshield if it's folded down.
I know my 97 owners manual explains what they're for, I'm just too lazy to dig it out and look it up.