Your question is Design a Feature Similar to Facebook iOS App. Take a moment with it on the right.
Talk me through your thinking if you like. When you're confident, submit your answer and I'll grade it like a real screen (7/10 or better passes).
Are you familiar with a particular multimedia feature of the main Facebook iOS app? How would you design that feature (screens, data layer, network layer), weighing alternative designs?
Asked in the loop system design stage. No code is expected, use diagrams where helpful. Be prepared to compare alternatives explicitly, including their impact on user experience, reliability, performance, and maintainability.