1. Hit your contact tab on the left.

2. From here Choose Tasks next to the contact phrase. Hover over it and hit import list:

3. Once you've opened this box, you now have the opportunity to import your email list into Big River:

4. From there, certify that these are allowed to be emailed and you'll be finished importing in your email list. (Please be sure to have the emails in the proper form and named so they will live in your contacts forever. You also don't need to make them User Accounts.)