Don't know about the "yellow" detail, but my Sterling Alternator controller is about 5 years old. As we are both in Cornwall, I could easily provide a copy of the instructions if it is likely to be the same model.
First, you have to decide which type it is, they all look similar! The original analogue and digital modles needed connections made to the alternator brushes. The latest digital does not. Look on the Sterling website for installation details.
Try ringing Sterling direct with the serial number. They should confirm type and send instructions. If you get desperate, I think that Skipper_Stu used the analogue version on Sonsy Lass. You could pm him for help.