This article explains how to connect Distil.ai to Mailchimp so that you can push and pull Audience data from Mailchimp into your Distil.ai Single Customer view and push new Audiences back to Mailchimp.
Login to your Distil.ai account and navigate to Settings > Integrations. Select the Mailchimp Logo to bring up the New Mailchimp Connection screen.

To connect to Mailchimp you need to provide an API Key.
To do this open up a new Tab/Browser and head over to your Mailchimp Account. Select the Account option from the lower left context menu.

Next, select the API Keys option from the Extras menu.

And finally, click the Create A Key button. This will provision you a new API Key which you can name as you see fit. Distil.ai would seem an appropriate option here, but you can enter whatever you like.
Copy the long alpha-numberic character sequence that is the key and return back to Distil.ai. Paste the key into the appropriate field.
Before you can save and continue you need to ensure that the connection is working. Press the Test Connection button and wait for Distil.ai to authenticate with Mailchimp. If everything is ok you will see a Connection Verified message slide across in the notification area.
Go ahead and hit Save. Distil.ai is now connected to Mailchimp and is available to both pull data from Mailchimp into your Distil.ai Single Customer View, as well as push Customer Segments back out of the Distil.ai Single Customer View into Mailchimp.