To mount the mantle to the wall, I attached vertical poplar mounting cleats to the wall just inside of each pilaster and one horizontally just below the top mantle shelf. I used my brad gun to nail through the pilaster sides and into the cleats. After positioning the mantle shelf flush to the wall, I drove brads along the rear edge into the top cleat and along the front edge from below. I positioned the bead molding around the firebox opening and tacked it into place. I finished by filling all the nail holes.