Prepare the ceiling:
Turn off the power supply from the breaker box. Medallions are ideally placed in the center of the ceiling. Locate the center of your ceiling by drawing two straight lines from both set of ceiling sides to the opposite side. The lines will interact at a 90 degree angle which is the center point of the ceiling.
Use a damp sponge dipped in soapy water to clean the area you want to place the medallion on.
Place your medallion on the ceiling and mark its circumference on the wall using a pencil.
Cut center hole:
If you want to attach a lighting fixture to the medallion, measure the canopy cover. Drill a hole in the center of the medallion using jig saw and drill so that you can attach the fixture to it.
Lay the medallion face down on a surface that will not ruin its design. Apply adhesive to the whole back using a putty knife and spread it over the entire surface. Before applying adhesive, you can also paint it in any color you wish.
Lift the medallion, place it over the area you marked for it with the electrical box in center. Take the electrical wiring out of the hole you drilled so that you can attach a fixture to it later on. Use putty knife to apply any adhesive needed or to clear excess adhesive.
Use the drill to insert two screws through the medallion into the wall to secure it fully in place. The number of screws you need also depends on the size of your medallion.Use caulk to fill up the screw holes and later paint over them.