As Bill says, the three sided rubber snaps into place. You have to work it in with different non cutting "tools" until you hear it pop. The forth side is riveted and I believe I bonded the division bar felt into place with 3M super weatherstrip adhesive. For the run channel there is a keeper down inside for the bottom and the rest I use tiny screws at/near corners and 3M and clamps. The run is the hardest part for me. Getting the vent glass back into the frame is hard also. Cut that run after the vent is all in place and cut it long because no matter how you measure it , it will sink in deeper and be too short where it meets division bar. You may not want to bond the run at all, some folks do not, I do. Have fun with those anti rattle wiskers, the nubs don't match the holes and you can't push in, no access. I shaved some of the nubs with a die grinder a tiny bit. What a hassle.
