Dark Oak slabs are half versions of their respective blocks. And it can occupy either the top half or the bottom half of a block, or both. To make Dark Oak Slab, you just need two things, Dark Oak Tree Logs and Dark Oak planks. Please follow the following steps to make Dark Oak Slab.
Dark Oak Tree Logs
In order to make dark oak slab, the basic item you will need to get is dark oak tree log. You can find these trees in roofed forest biomes. Use your iron axe to get at least 1 piece of dark oak tree wood.
Dark Oak Planks
Make your way to the crafting table to craft wood planks from a Dark Oak wood block. Open up the 3*3 crafting grid and add Dark Oak wood block in any cell to get dark oak wood planks in the right-side box to the crafting table. One Dark Oak wood block will convert into 4 wood planks. Bring these wooden planks into your inventory.
Dark Oak Slab
Now you will be able to craft Dark oak slab using the crafting table. Add three dark oak planks in any row of the crafting grid as shown in the image below. You will get six dark oak slabs in the right-side box to the crafting table. Add these slabs in your “ready to use” stock.