Coal walking, or the walking on coals by will of mind, is a incredible experience. Coal walking is just a few steps and walking over the hot coals is simple. The trick is not minding the heat.
To start you have to meditate on not seeing the coals and heat is not felt. Do this for at least 20 minutes. When you feel ready, stop meditating. Now, approach the pit of hot coals. Focus on the far end of the pit with your eyes. Know and focus on the thought of not feeling the heat. Now walk across as fast as you can. When you reach the oither side, their should be only blisters on your feet. If you are good enough there should be no blisters at all.
A preparation: Get immune to intense heat by being near it often as you can. Also do the meditation for months in advance! Walking on a furnace that is radiating heat has an immunizing effect to your feet.