Step 5
Now repeat step 1 and 2 and you can duplicate it
Step 3
If you get this error you doesn't set the gamerule(Step 4)
This is the block
A Duplicator
Step 1
Get the Item you want in your hand
The GUI
Its very easy
Step 2
Put the Item in the Slot and click on Duplicate
Step 4
How to enable the gamerule