Connecting the Amp Remote Wire
You now have the power sorted at the amp end. You still need to sort the power wire at the battery end, but can be done last. Your next mission is to run the remote wire down the same route as the power wire from the headunit. Most headunits have a labelled wire saying remote. If not, then you will need to locate a powersource that only turns on when the headunit turns on. Failing that, tap into the continuous 12v power supply, and add a switch to the wire so you can turn off the amps manually. Just dont forget to switch it off otherwise your amp will stay turned on when you leave teh car or turn off the HU.
When you've located the right terminal (or made one
You can now put back the trims on the side of the car that had the power wires running through.