FORD 1999 F-150 - Manual (Page 74)

3. Pull one side of the cover outward and upward away from the side rail
working from the rear to the front.
4. Starting from the opposite side of the vehicle, pull cover away from
the side rail and roll the cover from rear to front.
5. Secure the cover behind the cab with two straps.
The cover may be removed from the vehicle by sliding it sideways out of
the front rail.
Controls and features
74