Transitioning baby to crib

Right now my son who is 6 months old, sleeps in a pack n play in our room (the crib doesn’t fit in our room) his pediatrician wanted him in our room until he was 6 months old. Yesterday I started trying to transition him into his crib in his own room for naps. I have a rocking chair in his room so I sit in there with him, I keep the room dark and have his sound machine in there. Yesterday he took 3 very short naps in his crib, which is a start. But I think he became very over tired and had a very hard time sleeping last night. I’m trying it again today and he absolutely refuses to sleep, he was tired and ready to nap, as soon as I put him In his crib he wanted to play, rolling all over the place, threw his pacifier on the ground, talking and screaming. His pediatrician wants us to start having him sleep in his own room at night and I feel like this transition is going to be a lot harder than I thought. Does anyone have any tips or advice that would help this process? I’m a first time mom and honestly have no idea what I’m doing. Thanks!