This pic is easier to see and adjust the flames. In emergencies, a liter of lamp oil or kerosene can cook beens and rice for a week on just three wicks, but your results will be different.
If you must use inside, always keep a window open. The safest place is inside the oven. Place burner on a cookie tray of wet sand or gravel, use upper rack to position pot.
Check constantly! Never let flames get high enough to smoke. If used in oven, leave door open. Keep food covered (aluminum foil is better than nothing) to speed cooking. Also, use foil to concentrate the heat under the pot. This is easy, just wrap around pot sides, fold as needed, and affix foil 'cylinder' to thr rack under pot. When a coffee can holds up the pot, it traps the heat for you (and actually works better)
But what if you dont have kerosene or lamp oil?
Cooking oil (corn, veg, etc. Even used) will also work, but youll need more wicks for the same heat and it smells worse when it burns. Dont have that? Vasoline works too, but with it you soak the string in it, put a glob of vasoline in a tuna can, and arrange like wicks in a candle.
NEVER use gasoline!!