1. Navigate from the home menu to Manage.
2. Go to Lists.
3. Click the three dots on the right-hand side of a list.
4. Click Settings.
5. Navigate to notification settings.
6. In the List Review Group field, enter the email of the first person you'd like in your review group.
7. To add multiple reviewers, simply click Add Reviewer.
NOTE: You can add up to 27 reviewers.
8. After you've added all of your reviewers, click Commit Changes.
Now, when you're creating a message, you'll have the option to send a test to this group prior to launching the message to your list of contacts.
9. On the authoring page (Authoring > New Message) scroll to the bottom of the page and click Send Review. Now, each of the members of your review group will receive the message.