It’s very simple to use and functions just the opposite of a regular crafting table. Simply place the item you want the materials from in the left slot. Then just grab the materials from the right slots. It can be used on any craftable item including food.
If a normal recipe yields more than one item then you’ll have to place that number of items to get the full amount of materials back. If not you’ll only get the partial amount of items from the recipe. Also if you put damaged items in you’ll get only a partial recipe back. While this is only a slight drawback it works great for reclaiming raw materials like diamonds or ingots if you need them in a pinch.
A great feature of this mod is the ability to reclaim enchantments from enchanted tools. Simply place the enchanted tool in the left slot and a book in the slot below it. Then when you claim the materials from the right side, the enchantment will go back to the book you placed.