[SS Tim]

Good, Glad to see my hardware chart clip made it here as it supports what I said about the carriage bolt. Being a pretty typical hardware store staple it should be easy to find one.

There are a number of questions running through the thread so I am just going to hit what I can without a lot of quotes.

The spare rests on the floor, the illustration could be clearer in that regard. But the floor in fact is the primary load bearer. The simple fact the tire retention bolt slides freely in the slot should make that plain.

The carrier mounts as shown in the drawing. Tucking under the upper lip, the lower end swoops outboard (away from the centerline) to pickup the fastener line along the edge of the bed floor.

Since the wheel is retained with a lug nut, the provided wrench is all you need to tighten or loosen the wheel for installation or removal. The second back up nut... see post #71.

If you want to lock it, you have two period options. A keyed spare tire lock with a special nut you tightened then a cover f keylocked to, to prevent theft. They were once common as dirt but I am sure years of neglect and lost keys have seriously reduced their number.
The other of course is a chain (or cable) through the center hole around the carrier and one half of the wheel tire assembly. You could even do a full turn around the carrier if you wish.

Since peple seem really hung up on hardware just use what you can and keep looking. Like I said above a hardware store carriage bolt and a lug nut will get you started.