This process can be performed over a gas barbecue, your household oven or in a fireplace.
With a new Dutch Oven I recommend heating the Oven and scrubbing the inside to remove any wax, debris, or oils from the manufacturer. Some Dutch Ovens come "pre-seasoned" so please refer to the manufacturer recommendations when dealing with a pre-seasoned dutch oven.
After the pot is pre-heated and cleaned, oil or shortening should be added to the pot. Typically this is accomplished by wiping the interior of the Dutch Oven coating all interior surfaces with the shortening or oil. Then the oil or shortening should be baked onto the Dutch oven. It is recommended to perform this two or three times to get a solid coating that will prevent food from sticking. The seasoning procedure should only be repeated when the coating is damaged or when rust appears on the pot.
Following the pot's seasoning, foods that are high in sugar (i.e. cobbler) or acid (i.e. beans) should not be cooked in the pot, during the first few cooking sessions.