Article: The simplest way to do this is with a charcoal grill or fire pit.  If using a grill, light a medium size pile of briquettes on fire and fan them until they start to glow. If using a fire pit, light a medium size pile of wood mixed with charcoal briquettes on fire and fan the flame until it becomes strong yet controllable. Grab the handle portion of the metal with tongs, then insert the blade portion of the steel directly into the fire. Hold it there, rotating it occasionally, until the steel becomes medium red.  The steel needs to reach a temperature of about 1475 degrees Fahrenheit (802 degrees Celsius). You can check for the right conditions using a magnet. Once the metal is hot enough, a magnet should no longer be able to stick to it. At this point, the steel will be very brittle. Immerse the blade into a heat-resistant container of oil. Let it sit in the oil for several minutes.  Keep the blade vertical as it sits in the oil. Nearly any type of oil should work. Motor oil works well, but so does transmission fluid and vegetable oil. Place the blade in a kitchen oven preheated to 400 degrees Fahrenheit (200 degrees Celsius). Leave it there for about 20 minutes. The quenching process cools the metal down, but the blade needs to be at a temperature between 350 and 550 degrees Fahrenheit (175 and 290 degrees Celsius) for it to temper correctly. Once you see the blade turn a wheat color, the metal has tempered correctly. Allow it to cool down to room temperature in a safe location.

What is a summary?
Build a fire. Place the blade in the fire. Quench the blade. Reheat the blade. Let the blade cool.