As soon as a new email is received, the unread mail count in the Inbox increases by one. In the List of emails, the headers of the unread emails (sender and subject) are highlighted in bold.
To view an email, select it from the List of emails by left-clicking anywhere in the message snippets, but not on the avatar. The snippet of the message will be highlighted in color, and the contents of the message will be displayed in the Reading pane. The email will be considered read.