Primary Air enters the bottom of the stove (between the feet).
The density of the fuel bed limits the amount of primary air, which in turn causes pyrolysis of the fuel. Since the stove is lit from the top, the pyrolytic front progresses slowly downward, controlling the rate at which fuel is burned, making sure it does not burn too fast.
Secondary air enters through the bottom of the stove and travels up the sides of the stove, between the outer body and the combustion chamber. The secondary air is pre-warmed as it flows up.
The secondary air enters at the top of the combustion chamber, under a lip which helps mixing of the wood gas and the secondary air.
The flame occurs at the point where the secondary air and wood gas mix.