How to Create a View for Unread Mail

While you can use the Unread attribute in the Focus Pane, shall you wish to create a saved search for your unread message, you can create a Saved Search / Smart Folder.

• Go to the File > New > Saved Search... (Windows) | Smart Folder... (Mac).
• Give your saved search a name, like "Unread Mail", and then configure your criteria to read "Status -- isn't -- Read"

You can also specify which folders you want to pull mail from, and also the location of your saved search.