Surgeons.how do they prepare you surgery methods?

I am serious. How do they teach you in actuality cutting into someone's flesh, removing organs/tumors and sewing them up again CORRECTLY? By the channel, if you are a surgeon, you are pretty amazing! They throw you into the fire and have you do things little by little. You keep under surveillance a surgeon do it and you are expected to do it the next time. You also read more or less techniques contained by books, but the way a surgeon become a surgeon is by experiece in the operating room.