First, head over to https://app.datatrics.com/integrations/mailchimp/ and click on "Install"
​

After clicking on Install, you will see the following prompt. Click on "connect to MailChimp"
​

you are redirected to MailChimp to authorize:
​
​

After logging in with your credentials, the integration is completed.
​

Datatrics will now synchronize all profiles and activities.