the channel should stay on the glass in correct position or it will be a nightmare to refit in situ, Iirc the channel came in 2 types one had a hole and the other a groove, if its the one with a groove you pop the plastic slider clip off the mech ball and place it into the channel groove on the glass, then simply align the mech ball socket & clip and squeeze with grips, been some years since I did one but unless my minds playing tricks on me that what I used to do