David Hampton was a man who pretended to be someone else and convinced others that he was that person, even though he wasn't. Imagine if you dressed up like a superhero and told everyone that you were that superhero. That's what David Hampton did, but instead of a superhero, he pretended to be the son of famous actor Sidney Poitier.
He lied to people about his family and his background, and convinced them to give him money and even a place to live. It's like if you made up a story about your family being very rich and convincing your friend to give you their lunch money every day.
Eventually, people realized that David was lying and he got in trouble for it. It's never a good thing to lie and deceive people, even if it seems fun or exciting at first.