In an attempt to be useful rather than comical-- First some prep: make an accurate template or pattern of the frame of the gun where the grip has to fit. Flat sheet aluminum is good. Some sheet plastics would do. You will probably have to punch out the locating pin from the pistol frame to get access close enuf to the frame. Same applies when finally fitting grip to gun.
1. You need to select a surface area on the antler that will approximate the size of the finished grip, a bit bigger than minimum.
2. Next cut it out thick enough to flatten what will be the inside of the grip. Make it a little thicker than you think you will need.
3. Then start working it down from the inside, keeping it flat and getting the taper you will need.
4. Once satisfied your 'then made' blank is OK, use your above-mentioned template to carefully profile your grip. You fit your grip to your accurate template. If you try to use the gun you will eventually mark its finish. If finish on the gun doesn't matter, do as you want.
5. Repeated filings on your grip blank will get you to a fitted flat side that you can put against the gun. Some more off-gun fitting will be required for best fit. When you are satisfied with fit, clamp the grip to the frame and back drill thru the locating pin hole so the grip will fit the frame properly.
6. Assuming both grips are at this point you can locate and drill your screw hole. Copy the same kind of screw & screw adapters as on original grips.
7. Working off the gun, shape the outside of the grips to your satisfaction.
Notes: Having never made grips before, you will save yourself time and grief if you make at least one side grip of hardwood for the experience. It is good practice to do a fit-check before you get quite to what you think is right - it's hard to put back material you shouldn't have filed away. Accuracy in making your template is a most important first step - and be sure it doesn't get filed as you work. Make a new one if you need to.
Hope this helps.