The Right Cutting and Installation Methods
(A) Draw a line for the reveal you want on your installation. One quarter of an inch is traditional.
(B) Tack finish nails behind this line. You can then place the arch on these nails and they will hold it in position enabling you to accurately mark the arch for cutting to size.
(C) It is very important that you center the arch on the opening.
(D) Measure and cut.
Once you have cut the arch to size, put a continuous bead of a good grade construction adhesive on the back of the arch along the inside and outside edge of the arch, hand nail or use nail gun.