Bead construction adhesive around the inner rim of the back of the plate. If the plate is flat, smooth adhesive over the entire back surface.
Hold the plate against the wall. Quickly adjust it if needed. Then hold it in place for 60 seconds or more to ensure the plate has adhered.
Remove your hand slowly from the plate. Tug at the plate with medium pressure to make sure it stays in place. If not, hold it in place longer.
Prop a mop or other tall object against the plate to help hold it in place for 24 hours or more.