This is a very good basic tutorial for “fair use”.
By the way, the people in this video are in fact lawyers. Yet pay attention. They state clearly in the beginning that this is not specific legal advice.
“You shouldn't take this as legal advice. We're lawyers, but we're not here to give you legal advice today. We can't tell you what you can, and can't do, in any specific circumstance. Take today's discussion as general guidance, and things to consider.” --- Anthony Falzone, Executive Director of the Fair Use Project
I learned a great deal from watching this, regarding copyright , and hope others will as well.