This article explains how to send a test email template from the visual editor. To send a test template instance built into a campaign, see:
In the visual editor, navigate to the Preview tab.
Enter any email address and select Send.
To send to multiple recipients enter all of the email addresses separated by commas, e.g. firstname.lastname@example.org,email@example.com,firstname.lastname@example.org
Be aware that the View in browser link won't work for test sends.