I think the rear boot TOTALLY makes up the back-end of the convertible when the top is down, and have only driven without it on when I had taken it out for some reason (cleaning?) and forgotten to put it back in. Even if it doesn't match the color of the car, it "makes" the shape in the rear-end what it needs to be.
There are 4 straps on the front of the cover, two inner ones have velcro on the bottom of them, and those wrap around and stick to the under-side of the luggage compartment lid. (parcel tray)
The two little string-like ones with metal hooks on the end of them hook onto little notches molded into the plastic covers on the sides of the rear seat area, and are maybe about halfway down. I think mine used to be elastic, but they're all stretched out so I tied two knots in them to take up some slack, and they hold pretty snug now.
The black hooks on the rear of the boot hook into a little loop on each side of the rear of the top where it attaches to the body. These little loops are about 3/4" wide, and right above the rear corner on each side.
There is also a snap on each side of the boot, where the bottom edge stops near the rear window. These simply attach to it's mate snap, which is held to the car by a screw which also attaches part of the little plastic front corner cover of the bottom of the top.
I have found that the best way to put the boot on is as follows:
1. put the boot on without hooking, looping, or connecting anything.
When you take off the boot, remove the snap and hook from one side, then the snap and hook from the other side. Flop the boot down onto the rear seat, and put up the top. Then, lean back and lay out the boot on the parcel tray, this will keep the back seat neat in appearance, and although there is a boot on the rear shelf, it is there with purpose, and isn't as though it's back there to clutter things up. Don't forget to flop it back onto the rear seat before you put the top back down.
Then, when you go to put the boot back on all you have to do is flop it onto the top, and attach a rear hook and it's forward snap, then do the other side in the same manor.
Following this plan, it takes as little as maybe 40 seconds to put down one's top and affix the boot over it. If it's just a short trip and you don't have enough time to put the boot on, maybe you don't have enough time to put the top down to begin with, or you're being lazy. :P
2. hook one of the rear hooks, and then the do the snap at the front of the same side.
3. Do the same for the other side
4. Attach the velcro straps to the underside of the parcel tray
5. attach the little metal hook things to the plastic side-cover pieces.