Van: I can tell you how mine works and yours is likely similar. The pump and reservoir are located in an underberth storage area just forward of the cabin bulkhead, starboard side. There is a small filler cap on top of the pump housing. As I recall, I had to remove the smoke-colored plastic housing to accesss the filler cap. I also had to use a very small diameter funnel to avoid spillage. Also, bring a flashlight to read the 'fill to here line' on the reservoir. Boat should be level in the water when you check the fluid level.
Mine is easy. Hope yours is too.
Rob