How can you preview a message for a given subscriber?
Sometimes, seeing a preview of the email contents for a specific recipient can be a great way to spot check any dynamic content in the email (template variables, etc.).
In order to do it, first click on the Test icon:
Then type to search for a subscriber:
Then once you click on a subscriber, you'll see the preview refreshed with the contents for that subscriber:
Here's a GIF that shows the whole process: