Before doing the exercise, you should read The gist of the matter.
Tell everything you know and don't know about the object.
The Announcer says: "Dinosaur"
The Spokesperson says: "A dinosaur is an extinct animal that lived on our planet millions of years ago. It wasn't just an animal, but a whole class of animals. They were huge lizards, crawling, swimming, and flying..."
You speak, and the partner listens, then you switch roles for the next word.