The black plastic "filler ring" (#2996788) is installed from the backside of the steering wheel. It can only be installed one way since the mounting studs are clocked according to the spokes. Simply install the spring clips on each of the three studs and your done. Now install the adapter/horn switch bezel to the steering wheel, which is also clocked. Make sure to line up the two pins on the horn switch backside grounding plate, to the two holes on the steering wheel center base plate. If you don't, the medallion in the horn cover will not center properly when the steering wheel is in the center position.