Drill 5/16" diameter (Ø 8mm) hole. Fold anchor in middle.
Insert anchor in hole and tap flush with wall.
Insert key to pop anchor open & lock behind hollow wall (not necessary for thick or solid walls). Do not force or hammer key.
Place item over anchor. Insert screw and tighten until screw is flush with fixture. Then, stop.
The anchors also wedge securely in thick or solid walls, or in wood studs behind drywall.