Georgiatoffee, sorry for the late reply. Mark Plastics' windows are easy to install. They come with a trim ring and screws for the inside. To be expected prep work is everything. Get all the old sealant off. I used a plastic and thin, flexible metal putty knife. Work slow and carefully not to damage the fiberglass. Clean with mineral spirits. Dry fit. Mark makes the windows a little snug intentionally. In some places I used a dremel to grind a just a bit. Clean up dust. Sand outside edge of fiberglass cut-out with 220 grit sandpaper to ensure all old sealant and oils are removed so new sealant adheres better. I use blue painters tape around window opening for overflow sealant to make for easier cleanup. Apply sealant, Dow Corning 795, to the flange area of the window, insert from the outside, position, and screw in trim ring from the inside. I tightened the screws down most of the way. Went back a few days later and took another 1/4 to 1/2 turn on all the screw. Good luck if you do yours.
