1. Run /items creator.
2. Insert your item
If you accidentally close the GUI while modifying an existing item, the creator will store your item for you to edit again, ensuring changes are not lost.
3. Edit item properties
Each button allows you to configure a different aspect of the item, whether it be the attributes, set bonus, tier, item name, description, etc.
A full list of the editable features can be found on the
wiki.
4. Click the item in the center of the menu to retrieve it.