Misused is all about English words that are used wrongly in conversations. These words are words that sound similar but are spelt differently. This episode is about the misuse of I'M and AM. "I'm" is the contracted form of "I am": I am going to the market.
"Am" is an helping verb. It supports other verbs (action verbs) in a sentence. Also, "am" is a state of being verb. It tells you who a person is: I am an English teacher and also tells you what a person is doing: I am eating.