The Decorative Wood Wall is a building block that you can craft in your Crafting Menu (default key "q") after finding and learning the according rare Recipe Page.
Recipes can also be learned in player-created Adventures.
In order to permanently add the recipe to your crafting menu (and so it can be carried over to all other Creativerse gameworlds like all rare and store-bought Recipes), this recipe has to be learned at first by right-clicking on it in your inventory/bag or dragging it with the left mouse-button over your player character model on the right side of the inventory.
To craft 8 blocks of Decorative Wood Walls you'll need (as of R44 in June 2017)
- 2 Wood Slabs made of any kind of Wood (except for corrupted wood) or Log in a Processor
- 2 Wood Rods made of any kind of Wood (except for corrupted wood) or Log in a Processor
- 1 Obsidian Rod made of Obsidian (bars) in a Processor
Attention: Decorative Wood Walls are flammable! When placing Decorative Wood Walls into hot environments close to (or especially directly above) torches or fiery blocks (like Hardened Lava), Decorative Wood Walls can easily start to burn. Liquid Lava or Fire Bombs will immediately set them on fire.
If Decorative Wood Walls start burning, also other flammable blocks nearby can catch fire, and in this way a whole wooden house or forest (especially Wildwood, Parchwood and Shorewood) can burn down in hot biomes like Jungles, Savannahs, Shores or on the Lava layer.
Fire cannot be extinguished currently, it can only be stopped from spreading by creating forest aisles/swaths wide enough so the flames cannot leap over, or (since R33) by claiming the area and disabling the fire spreading option for the claim.
On worlds of players who bought the Pro DLC, the fire spreading (fire sim) option can be disabled for the whole gameworld. On player claims, fire spreading is disabled by default, but can be enabled by claim owners.