More than likely the red line is your pressure into the loader valve. The green is your power beyond (pressure out) and the orange is your return to tank line. The fitting under the green line is most likely the power beyond adapter plug.
If you want to make it simple and as economical as possible, just run a line from the green port to the back. Have a set of couplers at the back. Then run a return line to were ever the green line now connects. This will make a complete loop. Couple the hoses at the rear together or uncouple and insert your log splitter. This will work as is. If your log splitter is a 3 line system, then you will need to tee into the return to tank link with the return to tank line on the splitter.
Pretty simple, just have to remember that the lines at the rear MUST ALWAYS BE COUPLED, either to themselves or to the log splitter.