In the place that you are going to bake the food (in a large fireplace, barbeque in the garden or a brazier) begin by heating the tserepa. Make a good fire with wood or coal. Place the cover of the claypot slanted on the fire so that it heats well on the inside. When the coal is hot and ready and there is enough ash, clean an area, place the tray and cover it carefully (very caferully so that you don't break the lid which will be very hot).