Desperate for help 🙁

My baby is 4 days old today but we're having a hard time putting him to sleep. He HATES sleeping on his back. So when we put him in the crib within 2 minutes he's up screaming but if he's on his stomach he's fine but that isn't very safe the nurses said so we don't do it. And also it's almost like when he realizes he's not being held like when he can stretch his arms and legs out he freaks. We tried swaddling, music, rocking him into a deep sleep then putting him down but nothing works. I don't know how to make him fall asleep and for a longer period of time so he can get the rest he needs. Anyone have any advice?!