Your Model 3 has a rear console integrated in the center of the second row seat back. Pull the console down to access the rear cup holders, or use it as an armrest.
Coat Hangers
Your Model 3 has a coat hanger on each side of the vehicle in the second row. Push the coat hanger to release it. Push it again to retract it.
Cabin Camera
Model 3 is equipped with a camera in the cabin. The camera is not currently active, but might be used in potential future features which could be added to Model 3 with software releases.
Keep the camera lens clean, and free of obstructions. Remove any buildup of dirt or dust by occasionally wiping the camera lens with a soft damp cloth.
Caution: Do not use chemical-based or abrasive cleaners. Doing so can damage the surface of the camera lens.