What does the Classic Outlook (as opposed to the New Outlook) look like and what are some of the names of the parts of the GUI (graphical user interface)?

The Navigation Pane is the narrow vertical bar on the left edge of the Outlook window. It has buttons that allow you to switch quickly between the various Outlook modules (such as Mail, Calendar, People and To Do). It also has buttons that open other Microsoft 365 apps, such as OneDrive.

Reading Pane – Also known as the preview pane, this pane allows you to read items without opening them. You can customize the reading pane by repositioning it, hiding it, or changing its size.

Below is a screenshot of Classic Outlook. I have a Microsoft 365 account. I also downloaded Outlook and pinned the program to my Taskbar at the bottom of Windows for easy access to Outlook. I have used Adobe Photoshop to add the red text and arrows to draw your attention to some area of the interface.