3. Engine Cover Exhaust: Usually the engine cover stops much more abruptly at the rear of the car that when the 'device' is fitted. The additional exhaust section serves a few purposes: It allows the addition of the periscope that extends upto the rear wing but also acts as an exhaust for the airflow which exits into the beam wing Monkey Seat / Mini Diffuser.
4. Periscope: This is most important aspect of the whole system as it's how the air is transported to the underside of the Rear Wing in order to create the additional downforce at low speed and 'Stall' the rear wing over the speed threshold. In the picture below Lotus had the ejector holes taped over in order to stop the device operating (due to bad weather conditions)
5. Monkey Seat / Mini Diffuser is placed / being used in order to take advantage of the situation presented by the device in general. By adding this Diffuser shaped Monkey Seat the airflow will be pulled through the exhaust as Downforce is generated on top.