It really depends on whether you are talking about a new corn from a breeder that has already fed the snake, or a new snake right out of the egg. If it is a new snake right out of the egg, you wait until the snake sheds for the first time, and then you feed him either a live or a f/t newborn pinky. It is best to feed him in a small container like a deli cup. If the snake is from a breeder and has eaten previously, then you typically wait about 3 days for the snake to settle in and settle down, and then feed it a newborn pinky. If the snake came in a deli cup, it is best to keep the cup for the first few feedings.
In either case, if the snake doesn't eat the meal in about the first 2-3 hours, then remove the pinky and try again in another 5 days or so. If it still doesn't eat, then read up in this forum about what to do next.
Mark