How to Mirror Your MacBook to a Classroom Display (wired connection)

If your classroom display is showing a different desktop than your MacBook, follow these steps to show the same image on both screens.

Steps:

1. Open  Apple menu → System Settings → Displays.
2. Click the image of the external display at the top of the window. (1)
3. Click the Use as menu. (2)
4. Select Mirror for Built-in Display.

Want to use the classroom display as a second screen instead?
Follow the same steps and select Extended display.