Its not fun unless you love wood working. If you have enough of the old stock to get the dimensions where the stock fits into the receiver, write those down, then put the old stock against a stock blank and trace it out. remove the big pieces with a saw until you have a rough outline. Then use a big drum sander to bring to much closer outline. Mark your center line all the way around end to end, pencil the shape on the ends, then use a belt sander with 60 grit to start shaping. Once you get close, start on the receiver to stock fit, go slow, don't remove too much, this is usually done with a wood chisel to start, if you have access to milling machine then that's the way I would go. The main thing at this point is staying centered, check your side wood removal often against the center line. Once you can get the wood close enough it will enter the receiver a little, use a soft mallet and kind of pound it into place, not hard, but hard enough it will mark the places you will need to remove more wood until you have a complete fit. Mark your screw holes, remove stock and drill, mindful of the original angle. Sand and finish.
I would check with your local gunshops and ask if they have any take off stocks you could go through, 1 might be close enough to save a lot of work, my local gunstore has a barrel full of them.
Good luck.