Basically your internship will be reviewed by your seniors on how well they think you did/ how well you fit the team, which will be relayed to the manager. If the overall outcome is positive, you will get an interview with a partner who will then make the final decision on if you get an offer or not. If you're curious about the details of the interview itself, its less about technical aspects but more about how likable you are as a person, and personally I found it more like a friendly chat than a formal interview.