Drilled holes from the battery box in the center seat (was the factory livewell). I welded a 3/8 round rod to a 15/16” spade bit to easily chew through the styrofoam. I did this on the front bench; trolling motor wires, lights and fish finder. And the rear bench for; bilge pump, livewell pump and lights. I used a piece of flexible 3/4 bilge hose attached to the shop vac to chase the holes to get all the tiny pieces of styrofoam out.