[kevins2]

Those are likely "lift the dot" fasteners and, if you look closely, there is a small raised dot on one end of the chrome plate of the fastener. If installed correctly, it should be on the outside of the tonneau cover so you would essentially lift from the outside. It sometimes helps to pull on the cover (toward the outside like you're trying to stretch it). If you get two fingers under the outside edges of the fastener - one on each side of the stud - and then pull and lift, it should come off.