Measure the room perimeter
Choose the crown molding profile and material
Find and mark wall studs
Locate and mark ceiling joists if needed
Determine the spring angle of the molding
Cut test pieces for inside and outside corners
Use a miter saw for corner cuts
Cut pieces upside down and backward on the saw
Dry-fit each piece before installation
Apply adhesive to the back of the molding
Position the molding against the wall and ceiling
Nail the molding into studs and ceiling framing
Fill gaps with caulk
Fill nail holes with wood filler or putty
Sand smooth after filler dries
Prime and paint or finish the molding