Poulan S25D Chain Saw--HELLLP!!!

The problem I'm having is a LOT of slack in the chain, and no apparent way to adjust it. I've taken the cover off on the chain side--it's held on with a single allen-head bolt--and, other than two mating plates that go under the cover, I'll be #@$% if I can figure what's supposed to keep the bar adjusted to the point that the chain doesn't get excessive slack in it. It's to the point now where I have so much slack, I'm afraid the chain might untrack from the bar and come off and possible hurt either me or any bystanders nearby.

Does anybody know if there maybe should be a couple of bolts/screws that go into those mating plates below the cover? If not, what the Sam Hill keeps the bar adjusted?

I bought this saw at a farm auction of a family friend. I knew he only bought quality stuff, and he took good care of it. The Stihl I'd originally planned to buy--which showed a lot of usage--went for more than I could afford, but I probably paid a little more than this one was reasonably worth because I needed a saw, and I couldn't afford a new one. I heard this one run at the auction, so I knew it was OK.

But when I got it home, it wouldn't start...acted like it wasn't getting fuel. I pulled one of the covers off, and I found that the fuel line was so brittle, it crumbled when you touched it. So I took the saw to a friend who recently opened a small-engine shop, and he replaced all the fuel line for me for a nominal fee. The saw now runs like new, and I'm tickled with it. If I need a new chain--or a bar--, both Tractor Supply and Wally-World carry 'em, so one way or the other I can get one day or night!