How is the factory jack mounted?

The jack goes on the inside of the trunk on the right side (should be brakets) and it is elevated on the forward end.

The handle goes through a loop sticking up off the trunk floor right under the mechanical portion of the jack, and a spring goes from the jack to that same loop.

The base goes in the center of your spare tire and acts as a sort of washer/hold down for the spare and the big wingnut goes on the threaded shaft that comes up through the spare.

I can't find a picture anywhere, but maybe someone has one handy.