Buy and download the latest version (opens new window) jar-File and place it into your plugin folder, then restart or reload your server. Keep in mind that you will only see the resource when you have created an account on spigotmc.org.
With 1.14 being different the default configuration file had to be changed, this may cause issues on older versions. Since 1.13.x configuration file did not work properly with 1.14 so needed an update. If you find yourself in a case where it does not work on your version properly, simply try renaming the items, for instance: LEGACY_ENDER_EYE to get it working for version below 1.14.
When you found a strange behaviour make sure to remove op status and if used the * perm aswell. Than only add the safarinet permission nodes to your server/person, while making sure the perms used are enabled as per config(i.e permission per mob).