Measure each wall and mark the molding length needed
Cut the molding ends at the correct miter angle
Dry-fit each piece before installing
Locate and mark wall studs
Apply construction adhesive to the back of the molding if desired
Position the molding tightly against the wall and ceiling
Nail the molding into studs and ceiling framing
Use a nail set to sink nail heads below the surface
Fill nail holes and seams with wood filler or caulk
Sand smooth after filler dries
Prime and paint the molding if needed