OK the quick connect that is on the tractor gets opened and becomes half of each of the two quick connects shown on the schematic, drawn with loader in place. If the Power beyond at top has a plug in it as it appears, and if a power beyond sleeve is not included, I will assume you plumb this just like a Jinma using the "two hose" method. this gives the best flow to the loader, but prevents moving the 3 point at the same instant you are lifting the loader. not a big deal. All of the flow goes to the 3 point when the loader is not being moved.
This appears to be a similar valve design as used on Koyker loaders, power in on the bottom, return on the side at the top, pb on the very top (with an added sleeve replacing that plug).
1. The half of the existing quick connect on the tractor that leads to the pump gets attached to a matching new quick connect (or replace both sides, both must ahve the same type of check valve, ball or cone or problems can happen). This quick connect will get attached to a hose that goes to the bottom of the Loader valve,
2. connection "T" on the valvel get a new hose attached and on the other end, a new quick connect that will attach to the one on the tractor you didnt use in 1 above. This should lead to the lift box on the tractor. At this point, if you have oil and everything is connected you could start the engine and try the loader valve and 3 point valve if they work, you can start on the backhoe.
3 Since you don't have a tank on the backhoe, I will assume that they intend to run it off the tractor pump and hydraulics. If I remember right, the DF uses the transmission oil for hydraluics, like Ford and John deere (filter maintenance is very important on this design) if so, this will be plenty of oil for the backhoe, but even if I am wrong here, it could work. You can choose either of the quick connects in 1 or 2 above and open it up, the side that is closest in line to the pump will go to the pressure line on the hoe and the other will attach to the return line.
The idea is that you want all the valves in series. The only place you can use a T fitting (not to be confused with the "T"port on the loader valve) is on the return line in a system that uses the power beyond. (your actual return to the resevoir is inside the lift box on the lift valve and dumps directly into the tank on the "two hose" method.
I too will add a disclaimer that I have NEVER put a loader or backhoe on a DF tractor, Never installed a Bush Hog loader (if the book you linked to is hte model you have, be carefull it seems like a LOT of loader capacity for one of these tractors) So I cant make any guarantee that the info I am posting is accurate. But if I had this in my shop, this is the way I would proceed.
Best of luck!