After choosing the extractor that fits the hole you just drilled, place it in the hole and smack it forcefully with a hammer so that it bites into the screw. Be careful not to shift the extractor or put any lateral force on it after you’ve “set” it into the screw. You can see in the picture how the sharp edges on the extractor bite into the screw and are twisted counter-clockwise such that it grips better as it is turned outward.