You light a furnace in minecraft pe the same way you would in the PC edition. Once you have placed the furnace in your desired location you need to tap on it. Then when the screen appears you tap on the bottom box. Put coal/anything wood in. Then tap the top box and put what you want to cook/smelt in and wait for it to finish. Viola.
Put wooden materials, coal or charcoal in the bottom square and put something smeltable above.
To access a furnace in minecraft, simply click it!!!! Its that easy!!
Press E. It should leave the furnace GUI.
You can't...
How do I light pilot light on furnace
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 can't.
Burn cactus in a furnace.
Shift while you place it.