Hydraulic Circuit Diagram with description Needed

The above sketch shows a digger. Its overall mass is 5 tonnes. The extension of the arm is controlled by three cylinders, A, B and C. Cylinder A supports the arm from the chassis of the vehicle and cylinder C is between the bucket and the main arm.

Draw a hydraulic circuit diagram for the control of the three cylinders supporting the arm (you need not take into account the slewing controls) and produce an accompanying description explaining the functions of the main components.