Newborn sleep trouble

I have double posted this because I really need help but I wasn’t sure what group to put it in

I have a newborn and we have an old bassinet but he will not sleep in it. He won’t sleep unless he is being held which obviously is a problem for me and I don’t know what to do. We have a crib but I don’t want to put it together unless it will help him. He slept just fine in the hospital but now in the bassinet he rolls and then cries. I don’t know if it’s the mattress or just a newborn thing but I will take any advice that you have to help me. Thank you so much in advance!