If you need to export your contacts from Mailchimp so that you can upload them to your ActivePipe account, the following reference link may assist you with this process.

Once you have exported your contacts as a CSV file (in total or as individual segments or groups), you can upload them into your ActivePipe account. 

Make sure you have your contacts' first name and last name in two separate columns, so that your contacts can be greeted by their first name in your emails.