Frank's new toy

My new toy in a lister Petter diesel engine powering a Spencer Carter hydraulic pump, the reservoir of which you can see in the picture. The bit with the knobs is a dual flow regulator with "detent" flow controls. Two questions, can anyone explain how this detent control works? Secondly, does anyone know where I connect my hoses to power either a single ok double ram? The big fitment upper left is the return filter (I think), there are two 1/2" connectors on the dual flow regulator and there is the other connector, bottom left. Any hydraulics experts in the club or elsewhere in the ether?

Frank