Minecraft: Xbox 360 Edition

This achievement is pretty straight forward. Simply collect 3 pieces of wood from a tree, and place 2 of them in a furnace (one on top of the other) and wait a few seconds for the smelting to finish. Once it's done, you will get a piece of charcoal. Place that piece of charcoal in the bottom slot of the furnace and place the third piece of wood in the top slot. I'd also suggest putting an additional 7 wood blocks in the top slot, as a single piece of charcoal can smelt 8 items, and you wouldn't want to waste the charcoal. Each piece of wood will become charcoal, and once a piece is finished smelting, take it out of the furnace to get the achievement. Hope it helps! :)