I think you should click on you boat after going back to your island and then on the box on your right. Click on your item and then ''send back to barn''.
It will pop on your warehouse and you'll be able to use it.
(Sorry if some words are not the same, I use a French version).
It will pop on your warehouse and you'll be able to use it.
(Sorry if some words are not the same, I use a French version).