And just for completeness, the rule is there on page 9:
Acquiring Quests: At the start of the game, this Building
contains 4 face-up Quest cards. Assigning an Agent to Cliffwatch
Inn is the usual way to get new Quests. However, each action
space has a different effect.
You can choose any of the available action spaces when you assign
an Agent to Cliffwatch Inn.
Whenever you take a face-up Quest card, immediately replace it
with a new card from the Quest deck.