Instructions
Ignite the TNT with flint and steel. This requires an iron ingot and a piece of flint to craft. Using flint and steel shoots out fire.
Deposit lava onto the TNT. This requires a lava bucket. You must right-click to deposit the lava.
Place a redstone torch underneath the TNT block. Crafting this requires a piece of redstone dust and a wooden stick. Regular torches will not ignite the block.
Punch the TNT two or three times if you have an earlier version of "Minecraft." This is not possible in beta 1.7 and later.