Part 2 : Installation.
You will need the following wires.
Power cable : 4-Gauge should be thick enough. You need enough to run from your cars battery to your amplifier.
Ground cable : This MUST be the same gauge wire as the power cable. This will run from your amplifier to a grounding point. Any bare metal point on the car's chassis. Most people use their backseat posts, but this isn't always the best spot, try it there, make sure you sand the pain off, and if you get any noise find a new ground point.
Signal Cable (RCA) : You will need enough RCA cable to go from your headunit to your amplifier.
Remote wire : Any thin cable will do since this carries almost no power, you need enough to go from your headunit's wiring harness to your amplifier.
Speaker wire : 12 Gauge wire should be large enough. You need enough wire to connect your amplifier to your subwoofer's enclosure, and also enough to connect your enclosure to your subwoofer's voice coil, and then finally another couple lengths to connect the two voice coils together.
now you put it all in...
The power wire goes off of the POSITIVE (+) battery cable and goes into your amplifiers power connector. It will most likely be labeled +12v or PWR. This will have to run through your firewall, make sure if you drill your own hole that you put a rubber grommet around the hole so that the sheet metal doesn't damage your wire. Most people then run the wire under the carpet and backseat into the trunk.
The ground wire connects the amplifiers ground connector to a grounding point. As I mentioned before it's common to use the backseat posts, but this might not be the best, only way to know is to try.
The RCA cable plugs into the back of your headunit and runs to the amplifier's input connectors. You need a headunit that has amplifier preouts in order to hook up an amp.
The remote wire hooks to your headunit's wire harness, either the Accessory or Ignition wires, I recommend Accessory so you can run your system with the car off. This wire runs to your amplifier, and usually plugs in next to the power and ground wires, it'll probably be labled "REM" or "Remote," this is basically the on/off switch for the amp.
The speaker wire connects the amp to the subwoofer box. There should be a + and a - wire, hook these to the + and - on the speaker terminals on your box.
On the inside of the box you then have to connect the speaker terminals to a voice coil. Again, make sure + goes to + and - to -. You then have to connect the two voice coils to each other. Again, + to + - to -, there will be two wires going into one voice coil since it is connected to both the speaker terminal and the other voice coil.
Hopefully that helped...if not then you're beyond help