Icon fonts are loaded by "Class" Name.  This is the name to the right of the icon.  In areas that support custom icons (such as the social media section), refer to this class name.  For example, to add the Paypal icon, in the field "Icon", adding "icon-paypal" would produce the desired results.  The download icon would be added by adding "icon-download", etc.

For a full list, visit: mk024.monkpreview.com/_assets/fonts/mk024/demo.html