Login to your Hopin account, choose your organization on the left-hand menu and navigate to the 'Integrations' tab:
Scroll down until you find the Mailchimp integration:
Click the connect button, choose 'New authentication', login to your Mailchimp account and authorize the app:
Click next and choose the Mailchimp mailing list that you'd like to push your registrations to:
Click Finish and after a moment you'll receive a message that tells you the integration has been successfully completed.
Now we can test the integration! Navigate to the 'Events' tab and choose an event:
Use the 'Preview' link in your event to navigate to your event registration page (your event will need to have at least one ticket created, and will need to be published):
If you haven't registered for your event yet, you can create your own registration here; if you have already registered for your event, you'll have to create a new Hopin account and register for your event:
After you've registered for the Hopin event, check your Mailchimp and you should see that registration as a contact in your audience:
You're done!