By default, all new messages are placed in your Inbox. If you have mail filter rules, new messages can appear in places other than your Inbox. The number in parentheses next to each folder name indicates the number of unread messages within that folder.
If you are using the Conversation view, messages are grouped into conversations. When you pass the mouse cursor over the conversation, a tool tip displays the first line from the body of the newest message.
Double-click the conversation containing the message.
The Content pane changes to show the individual messages in the conversation. The Fragment column shows the first line of the message body. To open the message, click the line that contains the message you want to read.
If you have Reading Pane on, the message body appears in the lower pane. Otherwise, you must double-lick the message in the message list and it will fill the Content pane.
Double-click the message.
The message body appears in the lower pane. If it does not display, double-click the message in the message list.