how do you mount the spare tire in the trunk of a 2001 mercury cougar

That tire is a mess to get back in , is not it? There should be a sticker on the trunk lid, the trunk floor under where the tire goes, or on the back of the tire cover to show you how to restow the tire and various other stuff.

it goes under the floor of the trunk. there should be a screw and some other parts with it to hold the tire down. the whole thing is a pain and is really hard to get to fit back together. l just screwed the tire down and left the jack and tire iron in the space around it and they're fine.