Start by downloading the shop manual
Manual
In section 4 last page there is a drawing of the hydraulic block showing where a line to feed an external circuit can be connected. I marked up the drawing.
View attachment 693992
The selector lever on the block has to be moved to direct flow to these external circuits
P marked with orange arrow would be the supply to an external circuit.
Depending upon the type of circuit you would use port T or connect into Port C using a tee fitting
Since your interest is in supplying a backhoe valve, use port P as the IN on the BH valve and Tee into port C for the Tank port on the BH valve
Dave
M7040