We have two types of MailChimp integration:
1. The first one is to sync participants info with one of your mailing lists. It can be done on the "Participants" tab of your campaign, but you need to complete the setup first.
2. The second type of integration with MailChimp is the one you've already seen. It's useful when you are not able to integrate your campaign with your website for some reasons (e.g. you don't have one) as it has limited functionality. You will be able to send out a email with our referral template that contains special sharing buttons with built-in tracking referral links, but your campaign participants wont be able to monitor their progress, or use the unique link from the MailChimp email. They will be able to check their progress and copy their unique link from the Participant welcome email they receive, if you pick this option.