I cannot return to the base layer from the layers. What am I doing wrong??

Also, just a note about that chevron: it will be very difficult for a learner to click the chevron since it is a vector object. A learner would have to click the very tiny orange line of the chevron, which can be hard to do. I would insert a Hotspot (Insert > Interactive Objects) and place that over the chevron, then attach the trigger to that Hotspot. I've done that for you in the attached file so you can see what that would look like.