>>19232234well, you can pay attention to the stories told by the natives themselves, which happen to line up with the archaeological evidence
picrel is called nan madol, from the island of Pohnpei, which has an entire complex next to it of enormous multi-ton basalt columns apparently quarried many miles away with hand tools and carried via multiple outrigger canoe across open ocean before being placed precisely at right angles
or you can believe the natives which say that gods arrived from across the ocean in advanced craft following an enormous cataclysm where a continent sank following a conflict between rival factions
but to answer your questions directly, they traveled 4000 km+ across the ocean because they were skilled navigators who used the stars to find their way and very durable building techniques (including reed boats similar to those built in egypt). the legends say these skills were taught to the locals by the same gods who came from across the sea
highly highly recommend the Kon Tiki books by Thor Heyerdahl
