Your newly fixed boat is essentially a cargo transport. Once your boat is built, you can fill it with 25 items to take to the Lost Isles.
You do not have access to your regular inventory while on the Lost Isles. Likewise, you cannot access Lost Isles inventory from Cloudy Lands, so choose carefully, or have plenty of food available. Each time you travel, try to remember to take necessary items with you that will be needed to build the bridges, and clear items in the lost Isles. and when returning, bring items needed for crafting. There are NO HUNTSMEN and No crafting buildings available to place on the Lost Isles!
Once you are at the Lost Isles, click on the tent, and empty your cargo. It will go into your “tent” inventory on the Lost Isles.
Any item you chop, or blast with dynamite as well as collection items remain in your lost Isles inventory until you transport it back to cloudy lands! This will be a new learning experience. It was for me! It will be a challenge to remember to transport what is needed!