Instructions
Raise a villager's affection level until he has at least three hearts over his head. You raise affection when you bring the villager gifts or talk to him.
Talk to the villager on Winter 24, the day before the Starry Night Festival. He talks about the festival. Say "Yes" when he asks if you will attend the event with him.
Go to Alan's Tree around 6 p.m. To find Alan's Tree, walk up the hill next to Brownie Ranch. Your date waits for you next to the tree.
Wait for the Starry Night Festival to start at 7 p.m. At 10 p.m., the festival is over.