You have one setting: On. It is difficult to make the flames be low without it going out.
1. Build the fire so the ends of your firewood are burning, not the whole piece of wood, this enables your wood to go farther.
2. Place one piece of firewood in the cook area.
3. Put your kindling in front of it, and place two more pieces of wood perpendicular to the first with the ends resting on it, over your kindling.
4. Break up some dry sticks and place them in the same area in order to help get the bigger wood burning.
5. Light your kindling.
You generally can only have one good flame area, so cook your starch first, and while it is cooking prepare your topping.
Be sure to keep checking your fire and moving your logs into the fire area as needed.