When using Zapier to automate the process of importing Google Contacts into Mailchimp, users create automated workflows called Zaps, which send information from one app to another. To set up a Zap, users need to create a trigger, such as a new or updated contact in Google Contacts, and an action, such as adding a new subscriber to a Mailchimp list. The process involves signing in to both Google and Mailchimp accounts, setting up the necessary connections, and customizing the data fields that are transferred between the two apps. Once set up, Zaps can automatically add new contacts from Google Contacts to Mailchimp lists, making it easy to scale email marketing efforts.