The only use I know of is that if you take a stick and a piece of coal you'll get 4 Torches.
S= Stick C= Coal E= Empty space
EEE
CEE = Torches
SEE
Coal can't be turned back into coal ore once it is mined. Since there is no enchanting in Minecraft PE, there is no way to obtain coal blocks in survival.
You don't.
There are no flares in Minecraft. If you mean torches, you put a stick and a piece of coal in a crafting grid. The coal goes on top of the stick.
dig underground
A single piece of coal can perform 8 furnace operations in minecraft 1.6, so that means 8 pieces of cobblestone.
Coal is very common. Caves are a good source of coal, but if you are mining, coal is most common at y=48.
Underground
You can find coal veins almost anywhere. Look at the side of stone cliff faces.
you NEED a Cobble stone pickaxe.
you must find flint and tender and coal
Use a pickaxe
Mine Coal then craft a stick, then put the coal/s on top of your stick/s