crappy topic title.
Find a hole in the firewall or make one and run whatever gauge wire Kris recommends in the manual to the + terminal on the battery. You may want to use thicker gauge for future upgrades like amps. Make sure you put fuse inline next to the battery.
You dont need to run a ground wire. The car's body/frame is ground. Just run an 18" or shorter wire to bare metal. I usually try to find a nearby bolt that screws into the car frame/body and squeeze the wire in between.
The ignition wire needs to be connected to an acc/ign switched line. If you have a nearby socket, you can tap into the + lead there. Otherwise, you can run a wire to the fuse box and find an appropriate lead.
If you need more help, search google for car amplifier wiring tutorials. It's a similar process.
Originally Posted by EBoundEE
You don't have to worry about the wires getting wet, water will not hurt 12v wires.