Attached the trim tab and it's channel to the elevator. This involved attaching a channel to the open, trim tab cutout area between the left outboard rib and the rib on the left side of the elevator channel. The trim channel fits inside those two ribs and fits over the middle rib that's also on the left side. Once the trim channel is fit to the elevator, the trim hinge is placed between the top stabilizer skin and the just-installed trim channel, then drilled out and cleco-fastened. The aft half of the trim hinge slides between the top, leading-edge skin of the trim tab, is aligned carefully into the center of the trim tab cut-out in the rear of the stabilizer, drilled, and cleco fastened. Much easier than the horn installation.
Trim tab attached in the center of the left rear elevator by a hinge.