The first obvious thing to me is to remove the ones on your gun and go from there.
What kind are you trying to make? Wood, ivory, stag? Plain or target?
The hardware you need is probably available from Brownell's. Wood or other materials from various sources.
What tools do you have? M1911 grips are pretty plain, and for the M1911, the simpler the better. Most home workshop tools will do except for checkering, which can be had from Brownell's.
This help much?