Outlook Express will display four "panes" in the main message window, the list of folders (upper left), the list of messages (upper right), the "preview pane" which shows the beginning of the selected message (lower right) and the Contacts list (lower left). One of the message summary lines in the message list will be selected (default is the last one)

 

The layout can be altered by using the View/Layout menu to change the panes that are shown and their position.