What is a flowchart?

Okay, I have to do a web site design, and I guess you could call this a brainstorm.. I have to use a “flowchart” I don’t know what a flowchart is, or anything. I looked it up and it just looked very confusing to me. Any help explaining, if possible? It looked like the format that teeny bopper magazines use for quizzes. I don’t know how this will help me brainstorm, nor how to use it. Help, please.
What is a flowchart, and how do you use it to brainstorm?