The instructions for this assignment are discussed towards the end of this video from this week's lecture material:
Prepare a ~1 minute video explanation of something important about a topic you know a lot about.
Then, pick someone else's explanation video that doesn't already have a response and watch it. In your reply to them, explain back to them the thing they explained to you. What did you learn from their explanation?
Read the responses to your video - were you able to get across clearly the information you were trying to convey? Where was information lost between your brain and theirs?