After mining ores, now we need to smelt them into usable ingots. To do this, create charcoal by burning wood. Dump the charcoal and ores into the furnace and it auto ignites. Currently the ratio is 2 ores : 1 charcoal but may be changed in the future.
After waiting a short while, your glowing red hot ingot comes out! Cool it down in water or just leave it there to cool. Definitely don't pick it up with your hands.
Finally sit back and admire your shiny ingot collection!