There are four screws one in each corner. Possibly Torx drive screw heads. Once you have removed the screws, gently lift away the plastic ventilation grille for two reasons. The screws locate the plastic tabs which are an integral part of the plastic ventilation grille into four square cut outs in the bodywork. If too heavy handed when removing, the tabs can snap off. In addition, the plastic ventilation flap which is an integral part of the grille at the back of the grille is attached to a metal actuating rod which needs to be slided out. It becomes visible when you start to pull away the grille from the bodywork.