“Auto play" indicator allows you to track the slide duration progress visually.
Good to know
Time required to pass before the next slide appears is defined in Settings -> Slides - General section. Furthermore, you can override this value by specifying duration value for each particular slide in corresponding slide properties bar.
NOTE: By clicking on autoplay indicator, you instruct CU3ER to pause the slideshow. Slideshow will remain paused until autoplay indicator is clicked again.
Autoplay indicator settings are almost exactly the same as "preloader" indicator settings! The main difference is that you can set 'autoplay' indicator tweenOver animation, which is not the case with preloader. This is intentionally left out, because there is no particular reason to have tweenOver for preloader indicator.
For further autoplay explanation, please check Preloader section.