Find a location that is not flammable. For instance if you are stranded on a beach, the sand won't burn. If you are stranded on asphalt, that won't burn. If you are in the woods, and there's a chance the whole thing could go up in flames if you light a fire, then you must clear an area that is made of simply dirt with no obstructions overhead. Remember your whole goal is to be found.
Collect wood and other kindling. When writing with fire, you are looking for wood that is small, called kindling. This will get the fire going. Then you also want to collect slightly larger wood, which you will lay above that. This will keep the fire burning. Be careful not to collect wood that is too large, otherwise it will be tough to spell words.
Lay out your message on the ground. Lay the kindling down first and then the larger wood on top.
Dowse each letter with lighter fluid or other flammable substance you have with you. If you brought a bottle of tequila in the woods to celebrate, then it's time to pour it out. Remember you are in need of being found sooner than later.
Light a match and let it rip. You will most likely need to light each letter separately as you want to lay them far enough apart so that they don't all blend together and become one big fire.
Tend to your fire by adding wood. Keep throwing logs onto your message to keep it burning. This is especially important if you are in an area that people are usually traveling to. You may have broken your arm and need help. But if they simply see any old fire, they may think you are just camping and not trying to write a message to them with the fire.
