Here we go,
pic 1,
the horn button and on left the ring which is screwed to the steering wheel.
pic 2,
back of horn button.
pic 3,
close up of ring showing rubber lugs
pic4,
close up of one of the locating lugs with ears on back of horn button.
pic 5,
button on ring ready to be turned into the locked position.
Hope this helps.Sorry about the picture quality the camera is old.
Jim.