Here’s one of the best videos or explanations of any kind that I’ve seen about how to set up your engine instruments to monitor fuel flow. This video is from a Ranger Tug 27 with a Volvo engine display and a Garmin chartplotter, but it gives you a good idea of what to look for no matter what kind of boat or engine you have. Take a look: https://www.youtube.com/watch?v=QV9KFcPanVI