This quest will start shortly after stepping from the teleporter. Father, the brains behind The Institute will talk to you and invite you to step on the elevator. Follow the straightforward path until you reach the holding cell with the kid named „Shaun“. Talk to him and Father will reveal himself.
During the conversation, Father will recruit you to join The Institute. Even if you're not planning to, you can agree to join and do some quests for the Institute with careful consideration of your other faction affiliations. After joining the Institute, you'll have to meet up with the Division leaders. Their positions will be marked in the map. After talking to all division leaders, the mission will be complete.