The heat source should come from the top and bottom equally. Coals should be placed under the oven and on the lid at a 1 to 1 ratio.
Usually done with more heat from the top than from the bottom. Coals should be placed under the oven and on the lid at a 1 to 3 ratio, having more on the lid.
FRYING, BOILING, ETC:
All of the heat should come from the bottom. Coals should be placed under the oven only.
Adding wood chips to your coals under your oven will produce smoke. The smoke will enter your Ultimate Dutch Oven through the holes in the cones. This smoke will follow the heat flow inside your oven giving your food a nice smokey flavor
Almost all heat will be from the bottom. Place the coals under and on the oven at a 4 to 1 ratio with more underneath than on the lid.