First, communication is key. Be open and honest about your needs and boundaries. For example, if you have different living habits like one likes to study late while the other wants an early quiet night, talk about it and find a compromise. Second, respect each other's privacy. Don't go through your roommate's personal stuff without permission. Third, share responsibilities in the dormitory or shared living space, like taking turns to clean.
I don't have the exact details on how far along the Persona 5 manga is at the moment. Usually, you can find this kind of info on official manga publisher websites or from manga enthusiasts' discussions on various online communities.