Day/Night confusion🙃

My son is 2 weeks old and basically since the day he was born he sleeps all day long and stays awake during the time we should be sleeping (4am-8/9am specifically). And I am not sleeping at all. I have an 11 month old daughter and she has a set bedtime schedule (10/11pm-8am) and I’d like to try to get him to start sleeping during the night bc I’m exhausted but i don’t know how to turn it around.