I would suggest starting with a boxlock first but if you are going to give it a go I will offer the following advice. Completely disassembly the action(cocking rods can stay). I would inlet the top tang about 60% of the way then lightly start the bottom strap into the action and the semi inlet. You have to watch a lot of things at once, depth of action into the wood from the top and front, twist left and right, sideplate cuts. Looking at an old stock can be very helpful. Be sparing with your inletting black and go slow. If you have specific questions ask away. Good luck but again, I would suggest an easier project first.
