Click "Send Emails" and then the "Manage Address Book" tab. Under "To: (Recipient's Email Address)" simply follow the instructions provided.
Tip: Once the file is saved in .csv format, open the file and check the document for unneeded symbols or information. For example the text, "Dave's email" will cause an error while loading because the site as it does not recognize symbols in names. Please clear out any symbols like the following before uploading to the site: &,", SMTP, etc.