1: collect wood
2: click on the crafting recipe for crafting table in the recipe book
3: click on the crafting recipe for wood planks in the recipe book
4: repeat steps 2 and 3 in a pattern (crafting table, wood planks, crafting table, wood planks) until your inventory gets filled with more wood than you started with.
5: when you exit the recipe book, your inventory will be filled with "ghost items" and duplicated items. (this sometimes also works for other crafting recipes in the recipe book)
MC-115436 Item duplication using recipe book