Unless you're using tracking cookies all you need to do is inform them your site is using cookies. There's nothing to really consent for in that case. Session cookies, login cookies, and other technical non-tracking cookies do not need consent as they fall under the exemptions. Out of the box a Joomla + CB site doesn't need consent, but given the law you still have to inform them you are using cookies, which you don't need to use a banner to do as you can put that notice in the cookie policy of your site (e.g. as part of your terms and conditions page). As for your plugin it's wanting you to supply your tracking JS (e.g. Google Analytics JS) so it only runs after the user has given consent.