A furnace is crafted with 8 cobblestone blocks using a crafting table. The formation looks something like this:
[] [] []
[] O []
[] [] []
[] = Block of Cobblestone
O = Empty
To access a furnace in minecraft, simply click it!!!! Its that easy!!
Press E. It should leave the furnace GUI.
You can't...
You automatically get 1
yes
Smelt Cobblestone in your furnace.
Burn cactus in a furnace.
You put cobblestone in a furnace with something to cook it with
You put sand in a furnace
Shift while you place it.
Burn cactus in a furnace.
You can't.