I was in the same boat when I started with my first tractor. I was familiar the physics of hydraulics but not the applications of the components. I do as much of my own work up to needing special tools or heavy shop support equipment. First I purchased the manufacturer's shop service manual which explains all the systems in great detail along with one line flow diagrams. Then I purchased a book "Fluid Power in Plant and Field". i now feel confident between those and the expertise here on the forum I can solve most problems. I am still looking for a hydraulic manual specific for tractors with no results yet. Hope this helps.
Ron