You have 2 suction lines to your pump. The line on right of the valve seems to show the word “skimmer”. Please confirm that. Do you know what the line on the left may be? It could be a main drain or another skimmer. The valve is set that the skimmer line is full open and the line to the left is closed. so when the pump is running you should be able to look in the skimmer to see the water swirling.I’ve uploaded the pool equipments. I have an auto pool vacuum but also purchased a manual vacuum for spot cleaning .
Your return line to the pool are all tightly plumbed together. This would be line with the 320 Chlorinator on it. It shows to go to a line that has the word “floor” on it. Do you have returns that come out of the floor? Then there is a long horizontal pipe that goes down into the ground. Does that have a label on it? Maybe some additional photos is possible when you have time.
It would be better to post the pictures to your reply by using the Attach Files link below.