How does linking to sunless sea work?

Could I do the actions that will award bonuses now, and get the game latter and the game pick up from metaflags or something?

Or should I just trade in the item that showed up today?

Doing one of the actions adds a flag to your account.

Whenever (if ever) you point Sunless Sea at the account, it will see those flags and give you the in-game rewards. :)

Cool plays with his kitten too, just in case