You have to use cord..like window sash cord or a strong fine rope that will fit in the groove of the rubber....you need enough to go all around the glass with a foot or two left over at both ends. You need 2 people.. 1 on outside 1 on inside....Outside holds in place while inside pulls rope/cord to position rubber onto flange where it sits. Continue pulling cord slowly till it is all in place...Hope this helps...Roy
