paragrph correction?

"There may be difference based on the manufacture or type of balloon, but an ordinary balloon for three to four passengers is generally composed of following three major parts: an envelope, a basket, and a burner. The first part that looks like a balloon that kids play with is called an envelope. The envelope mostly takes up the biggest part of balloon because it is designated to hold the air. In other words, it has to be so huge as it takes such a great amount of heated air to lift it off the ground."

This paragraph contains too many errors and I need to modify them.

Can someone help me?