basically run some wires from your CD player to the back of your car (buy lots of speaker wire from your local diy shop) and just use the connections in the back of your cd player to link up the speakers in the back.

What i have made is about 4 stages on from that, i started with a basic few holes cut into a parcel shelf, then i got sum more speakers so made a false floor and cut the holes in there to put them in, then i got the 2 big ones, so i added 2 more side areas for that, then i added the amp to power them (600w, got a big red computer fan behind it) that comes with its own wiring instructions so thats easy to do. and but most of it is just general knowledge. BUT before you do anything at all, get a pencil a ruler and a tape measure and measure everything out, brainstorm some ideas and then put them all together. and then buy the materials you need and get to work ) oh and as a footnote, you see the hinged trapdoor... thats for my rollerskates and beneath that is my 5th wheel (spare) make sure you can still get at that whatever you do, because if you pop a tyre you cant put a 10 inch sub on there to try and roll home, know what i mean!