Dear bregtv,
Thank you so much for using our theme Education Base. You can check the available settings for the slider inside Appearance > Customize > Featured Section Options and check all the options there. http://prntscr.com/hybnfp If you need additional things than the settings, you need to customize the theme. If you are familiar with codes, you can check the codes inside acmethemes/hooks/slider-selection.php and customize as your need.
Let us know if you have any further queries.
With Warm Regards
Acme Supports