This plugin is bundled with theme. You can install it right from the theme.
This plugin gives you possibility to create powerful sliders for various situations. You can check its documentation to get more knowledge how to work with it.
Plugin is bundled in theme what means that some extra features(auto updates, premium sliders) might be blocked by plugin author. To unlock those features you will need your own license for plugin, that you can get it from here.
However it doesn’t mean you will not be able to get plugin updates at all. With theme update we always attach newest version of plugin. Plus in our designs you often can find sliders created with them, so you get ready sliders to work on:-)