Hi, luckily for you, there are a couple of AskHistorians flaired users who've taken a deep dive into the South Pacific - check these threads out

• /u/thefairyguineapig in There are huge gaps between islands in the Pacific, what methods did the Polynesians/Islanders use to discover them and to stay on course in a trip between two islands they already knew existed? Do we know how many/what percentage were lost at sea?.

• /u/b1uepenguin in How could Polynesians navigate so well without compasses or sextants and how could they build ships capable of traveling deep ocean?.

NB: There's also a section in our FAQ - Oceania FAQ

Since these posts have been archived, if you have follow-up questions for any of the users, just ask them here and tag their username (e.g. /u/someusername) to notify them