The picture below shows how a hot balloon works.
The images below illustrate the operation of a hot balloon.
Overall, a hot balloon has three main parts: the largest part is the envelope, the basket, and the burner. The hot balloon uses the hot air to fly into the sky.
Starting at the biggest part, the envelope has many parts that are linked together, and made from nylon fabric. These details form the balloon shape when it is filled with air. On the top of the balloon is the parachute valve which can open and close. Its important role is controlling the temperature Lower the envelope is the skirt made from flame-resistant material to endure the heat coming from the burner. The important part of the hot balloon is the burner. it is the engine which works by heating cool air to hot air.
Turning to the operational process, the burner transforms the air to be hotter, and then it comes to fill the envelope. Otherwise, hot air is inherently lighter than air from the environment. Thus the hot balloon can go upward into the sky.