What is a hot air balloon ?

When preparing for a flight, the envelope is spread out in the direction of the wind. A fan fills the envelope with cold air. When it reaches the desired volume, the pilot heats with the help of the burners which allows one to obtain consistency. Once in flight, the pilot periodically reheats the air trapped in the envelope.

More one heats, more one rises. To come back down, one can pull on the parachute cord that lets out some of the hot air or one can wait until it cools on its own. To slow down the descent, the pilot can spuratically use the burners. For the landing, the pilot completely opens the parachute, empties the envelope and refolds it.
Only the vertical direction of the hot air balloon can be controlled by the pilot, the rest is done by the wind.