If it is anything like my lw300, just grip the corners and pull straght away from the window. There are four spring clips, on in each corner. sometimes the clips come off with the cover. they are supposed to stay captive in the base. If this happens, pull the clips off the cover and re-seat them in the base pockets. The lamps in the 3rd brake light seem to burn out rather fast for me. May just be a lot of stop and go driving here in the NYC area. I bought a box of the lamps since many stores don't regularly stock the lamps.
Oppie
Anybody ever make it to a Saturn Homecoming in Spring Hill?