Apply finish to the cove molding. Place the molding in a well ventilated area and paint or stain the molding as desired with a paintbrush. Let the finish on the cove molding dry completely.
Measure the area where you are going to install the cove molding. Write the measurement down and then use a measuring tape to mark the measurement onto the cove molding with a pencil.
Cut the cove molding on a miter saw. Place the molding on the saw and cut it to size. For corner pieces, set the molding to a 45-degree angle and cut the one side of the corner. Repeat at the opposite 45-degree angle for the other side of the corner.
Set the cove molding in place and secure it to the wall with a finish nail gun.