How is the balloon inflated?

The basket is placed on its side and then the balloon's 'envelope' is attached and layed out by wires attached the the basked.

The envelope is then inflated with cold air using a portable fan. Once the envelope is nearly inflated, the burner is switched on and the air in the envelope begins to heat up.

The hot air  makes the balloon rise to an upright position. For there the balloon in continually heated until the is warm enough to lift off the ground.