What happens next?

How to kill time on a ship
Inspect a map of the ship and get your bearings.
This will be particularly helpful when you first get on the ship, regardless of its size, and it'll help at least a bit of time go by. Smaller ships should have a map with locations of life vests, fire extinguishers, and other safety protocol available.
Most cruise lines have a large map including a wide variety of restaurants, activities, and events. Take time to look look at the map provided and learn where everything is in relation to your room.