Next is to carefully work the glass in and under the flange. I started on the long edge without the the cut where ends of the rubber where it butts together. This is a bit stressful, you have to keep pressure on the glass, but if you push too hard in one spot you'll break the glass. This is a bit hard to describe and document, but it's a 3 step process. You have to get the rubber in to pull up and over the glass. Fist you get the glass to kind-of go into position. Then you use a full flathead screw driver to pull one corner of the rubber inside the opening. You have to then slide the screw driver down the length of one of the edge. The rubber won't really just go over the edge until all sides are "roughed in". Once you get the glass "roughed in" you can use a paint can key to go under the rubber flange and pull it up and over the glass. The glass won't fully seat until all four edges are in the rubber.