It's quite straightforward.
You need to remove the trim panel from the boot lid, which is held down by a screw where the handle is, then you need to remove the handle by releasing the clips with flat head screwdrivers. Then the whole panel should come off from the plastic pop-fasteners.
I routed one wire via the boot hinge rubber cable boot into the interior roof trim and up to the front of the car, the other cable goes down the rear pillar area down to the rear light cluster.