How do you get Brewster on your island ?

Upgrade museum donate 1 of each possible item, then talk to blathers daily till he mentions coffee shop. Then go on boat trip and find brewster & invite him :)

1- Only Resident Rep can unlock. 2- When time to unlock talk to Blather at museum for quest. 3-Take Kapp’n boat tour to locate Brewster and talk. 3- Go back and talk to Blather. 4- Museum should close for day. When open you should have Brewster.