If you look at the schematic on the course, lesson 3 – overview of the circulation system. Click on the i symbols to see in what the components are, they are in the correct order on the schematic. Work from left to right.
 https://stockwellsafetylms.com/courses/pool-plant-operator-online-course/lessons/03-swimming-pool-design-and-operation/topic/overview-of-circulation-system/