Measure the wall where the crown molding is to be installed. Use a measuring tape to get an accurate measurement. Mark the measurement onto a piece of crown molding with a pencil.
Place the crown molding flat on the table of the miter saw. Line up the pencil mark with the saw blade. Make the cut to the crown molding.
Place the crown molding into place and nail it secure with a pneumatic nail gun. This piece of molding should rest flat against the wall once installed.
Cut the second piece of the corner crown molding with a miter saw. Instead of cutting the piece flat, set the saw at a 45-degree angle and cut the molding to size.
Place a scrap piece of molding on the cut 45-degree angle of the molding. Hold the scrap piece so you can trace the molding outline along the end of the piece of crown molding with a pencil. Trace the molding details on the crown molding.
Cut out the traced molding outline with a coping saw. Work carefully and slowly so you can get a precise cut.
Place the coped molding into the corner and nail it into place with the pneumatic nail gun.