Running Wires:
First having someone help you to fish the wires is helpful. In the helm there is a hole where all the factory cables run to the back of the boat. I used my Flexible Cable Pick-Up Tool with 4-Finger Claw for getting the wires up inside the boat. Inside of the helm, I stuck the flexible claw by itself down to the hole until my buddy could see it. Then I pressed the end to open the claw and he stuck the cable in the claw. Then I gently pulled it back up through the hole and connected it to the Rear R&L RCA Outputs. (5-10mins). We did the same thing for the Sub remote volume wire.
Then I went to the rear of the boat underneath the seat near the batteries and drilled a 1/2" hole with a drill bit. Take caution to make you are clear of everything underneath before drilling. My buddy acted as my spotter outside the boat looking up under to help me gauge if I was clear to drill the hole. The I used the claw to fish that end up through the hole as well as the Sub remote volume wire. I wrapped both sets of wires in a loom tubing to protect them and then zip tied that loom tube to another set of factory wires that ran down the side of the boat that were secured to the plywood decking. If you don't have that you can buy some cheap cable clamps to screw to the underside of the decking. After I had everything connected and made sure it functioned correctly, I secured the rear wires coming through the hole to the floor with a small wire clamp and put the stainless steel wire vent to cover the hole. I also put the waterproof caulking in the hole to prevent water leaking in.