Done a couple of them and I agree with all of the above but if you don't have the book you have two choices, one piece or two piece lid. I like the two piece. (1) Experiment with shapes, sizes and positioning(2)Make a flat where your lid will be on the butt stock. (3)Lay out the female mortice. Note: they taper. Front being 1/16" narrower than the rear. (4) Chisel out female mortice: 1/4" deep, sides at 60 degrees. I eye ball the chisel angle and keep checking with a 60 degree 3 sided file, and smooth with the file.(5)Cut the male base piece. I use a band saw, router and file, but just about any kind of saw chisel and file work would get the job done. Fit the male base into the female mortice. Allow some room for expansion. File and sand the top of the male base down even with the stock. (6) the lid is selected for grain and figure(about 1/4"-3/8"thick). Normally out of the same wood as the gun stock if you can. Cut this out and glue the base and lid together.(Before gluing make guidelines where the lid will be centered) (7) Some had a cap at the rear of the lid and some didn't. Cap should be made out of same material as butt plate and keep with the contour of the buttplate(not 90 degrees to lid). Lid and base is filed to desired angle even with the inside edge of the butt plate.Attach metal cap with countersunk screws( I use epoxy as well), and do final shaping. (8)Install spring catch (these are not too hard to make) allowing room in mortice for movement, and positioning where it will catch on the inside edge of the butt plate. (9) Shape and decorate the lid. After rifle is finished I grease these up on the inside of the dovetail. Hope that helps and makes sense. Hard to explain without giving you pictures or drawings, but I'm still learning on the computer.