On the ‘Subscribers’ page in your account, click the ‘Add subscribers’ button.
In the drop-down list that pops up, you can:
Manually add an individual subscriber (Fill in their email, and first or last name — If you have permission, of course)
Import your list from MailChimp (Just use your MailChimp login to authorize)
Import your list as a CSV or TXT file, or by pasting addresses (Check out the info on the right hand side of the page for a reminder on formatting):
And that’s it! You’re ready to start sending.