Alarm Motion Detector Position

My wife and I are evaluating one of the Ring Alarm Security Kits. Must the motion detectors be in line of sight of the base station? Must they be installed at a certain height? If installed at the end of a hallway or room, will the motion dectector pick up any movement? How far away in feet will the movement be recognized? What are the constraints of these devices? Any learned-lessons that I should consider?