Julia is correct. I just added a hotspot over the entire slide to make it clickable. The hotspot’s trigger is set to Resume Timeline and then Hide Layer when Timeline Ends.
Did you use zoom regions at all, or just layers with bigger ("zoomed") images? I'm creating something similar--image with markers to click. I plan to zoom in, but then there's the challenge of making tiny objects within the zoomed area.
Not the designer, but I'm guessing that she added a hotspot that covered the entire slide, then added the zoomed-in image and text on top of it. If you only have one image as your background, you could also add a trigger to it directly.