Looking for a "Plan of Attack" on this 2011 E350 Convt. Just purchased at auction as-is and the top is not working(at all). I popped off the liner in the back and the pump is empty with some fluid collecting underneath.

Where do I start?? Fill up the reservoir, clear the codes and see if it operates, then trace the leak?? Should I manually open the roof first?? Where are the common points of failures in the hydraulic system??

I also attached a few pics of the rear interior trim. Are those water spots or evidence of hydraulic fluid leak??