Simplify the following text for a Grade 11 native English-speaking person.
Original: The first inhabitants of the archipelago arrived around 33,000 years ago from New Guinea , either by boats across the Bismarck Sea or via a temporary land bridge , created by an uplift in the Earth 's crust .
Simplified: The first inhabitants of the Archipelago arrived around 33,000 years ago after sailing from what is now Papua New Guinea .