When using “cardboard” style headsets, selection is though “Gaze to select”. When in cardboard mode, which is initialed by tapping the goggles icon in the bottom right, you get a small dark circle in the center of your view. This is known as a reticle, and is your focus point as you look around. Simply focus the reticle over the hotspot you want to select, and you will see a circular selection spinner begin. after approximately 3/4 of a second, it registers as a select of the hotspot.