There are multiple ways to do it, the best way for you depends on your wants and needs. The most simple way to do it is to run a hose from the factory outlet to the inlet of a 2 spool valve. The outlet of the 2 spool valve must be returned to the hydraulic reservoir. The valve and all of the add on plumbing must be capable of handling the high pressures generated by the piston pump. To use it you lock the lift lower lever in the raise position. Realize that you will not have live hydraulics and unless you correctly size the cylinders they will be slow acting and will generate several times the force that the equipment was designed for. Another more costly and complicated way to to it is to add a crankshaft driven pump up front and create an entirely separate system. You if you chose the right components you will then then have live hydraulics that operate at "normal" pressure and flow to be compatible with about anything you will be using that size tractor for.
If you are hydraulically challenged you should either go the simple route or find someone that has actually done one from scratch and knows exactly what you need. I modified two D-17s to front pumps and 2 spool valves but that was close to 50 years ago and I bought the pumps,mounts and drives from Allis Chalmers.