Display Settings for Duplicate (Mirror) or Extend on Windows Computer

When connected to an external display like a monitor or projector or multiple displays, Windows computers have two different display modes: Duplicate and Extend. In Duplicate Mode the computer monitor duplicates the monitor on the external display so that you see the same picture on both the desktop and projector. In Extend Mode the external display is treated as a separate screen so that you can have a different windows open on the projector and desktop. It is easy to switch between the two settings.

Right-click on an empty area of your desktop
Click Display Settings
Scroll to the Multiple Displays area and select Duplicate these displays or Extend these displays. You may have to test the settings and change them depending upon your personal preferences.
If you are using the "Extend" option, you may find that your displays are out of order from left to right. You can fix this by clicking the Identify button at the top of this screen and re-arrange the displays as needed to match your setup.