It is a nice plugin which adds a more advanced paging navigation to your WordPress site.
Be sure to download the latest version of each plugin and upload them to your wp-content/plugins folder. Then activate them. Chip Themes will do the rest.
Use pagenavi-css.css: Unchecked
I will recommend to uncheck the check box of pagenavi-css.css option, as Chip Themes have built-in support for style WP-PageNavi paging navigation.
You may be interested to know more about this plugin.