Lift and remove the top cover.
NOTE: Do not pull hard or pry at first. If the cover is difficult to remove, be sure that you removed all screws. If so, then do not be afraid to GENTLY pry with your flathead screwdriver. You may have to tug or apply gentle force to get this piece off.
For me, working one of the corners up, then sliding my finger between the top and bottom pieces of the chassis along the edges worked flawlessly. Try not to scrape any internal parts when you do this.