Sounds like a great project! First step, find a good piece of well-seasoned wood. Don't use chemically dried wood, it will rust the metal. If you use insufficiently dried wood, the stock will eventually shrink and possibly rust the metal it touches.
Make a drawing of what you want the finished product to look like. If you feel up to it, you can make a blank by filling a trash bag with sealant foam (I believe one brand is called Good Stuff), then carve the foam into shape, or find big pieces of styrofoam and build a model.
Have a plan before you ever start working on the wood. Work slowly, using the old wood as a pattern for fitting to the metal. Shape the stock the way you want it, then fit it to the wood. Use standard woodworking tools used for furniture making, not construction tools. Remember, once you take wood off your project, you can't put it back on.
Once you have it shaped to your liking, block sand it with 60, then 150, then 220, then 320 paper. Seal the wood with Tru-oil or other stock finish. Do not try to invent your own stock finish, as gun solvent will dissolve most everything you might want to use. Build up coats of Tru-oil a little at a time, sanding with 500 grit paper between coats. You'll know when you're done by looking at it, but if you have more wood than the military stock or fewer than 5 coats of tru-oil, you're not done yet.