Take out any slab (other than stone) place the slab on the ground, place another slab on top of the first (to create a double slab) remove the slab from your inventory, use pick-block on the double slab block you just created, place the block that was given to you, it is now a double-stone-slab block.
Linked issues
Comments
Why on EARTH Are you stirring up reports from nearly five years ago?
Please ignore this submission, it is a duplicate, sorry for any inconvenience.. go vote for the original! 😃