How should a newborn baby sleep correctly?

This is an individual difference. Nowadays, many babies, including my friend's baby, can lie on their side soon after birth, and they like to sleep on their side. If you straighten the board, they will lie sideways again soon, but this situation will get better after a while. It is not recommended to put things on the sides of the baby's head to make it flat, because it will accidentally cover the baby.