I started many years ago with some discarded stocks and a Brownells basic checkering tool kit. Then progressed to recutting some already checkered stocks and upgraded tools. I read every thing I could find on checkering and stock making and gradually worked my way into both.
A person needs manual dexterity, good lighting, and a lot of patience. Some say you need a checkering cradle. I don't have one, and I sure never had $500 piece of wood. All of mine were from American black walnut my brother cut and aged about 20 years.
It is not rocket science and I am not a professional, but think I can hold my own. Sadly arthritis has stopped me from doing much.
Here are an old, Ithaca SXS 1936 era, and a Fox Sterlingworth of the same vintage. I made the butt stocks and fore ends, finished, and checkered them .