There are metal attaching pieces with flat metal tabs that goe through slits in the self deck that need to be bent straight down. From memory about 4 of them. At the front there is a strip of vinyl and foam that is glued to the top metal of the car frame. You can use a heat gun or sharp razor blade to remove from the metal. Of course you need to remove any trim on the sides or rear that is holding the edges of the shelf deck board down. This varies depending on the body style.
Thanks again for your help.