it starts off with vometing, then mucas plugs and blood
What? Do you have any idea what your talking about?
It starts when progesterone levels decrease and prostaglandins are produced. They stimulate contractions, which are strong, as oxytocin is no longer inhibited by high progesterone levels.
After labour the baby is expelled. The umbilical cord is clamped and severed and sometime afterwards the placenta is also expelled (the afterbirth).
Due to the loss of the placenta, oestrogen and progesterone levels fall, prolactin is no longer inhibited so the breasts can produce milk. Oxytocin is released from the posterior pituitary gland, which forces milk out of the nipples.