Configure your displays

>>> Arrange displays

In System Preferences’ Displays pane, use the Arrangement tab to define the relative virtual positions of your displays (they don’t have to be side by side). Drag the menu bar strip to the display you want to be considered the main one.

>>> set resolutions

A display’s resolution can be adjusted in the Display tab. Default is the recommended resolution, but Scaled offers others. Holding Alt and clicking Scaled may reveal more options beyond the initial range that’s shown.

>>> Mirroring options

By default, additional displays extend your desktop, giving you more room to work. But should you want the same image to be shown on your Mac and all connected displays, you’ll need to put a check mark next to the Mirror Displays item.

>>> Detect displays

External displays should be automatically detected by your Mac (but ensure the correct input is selected on your monitor if it has manual controls). If not, hold Alt so the Gather Windows button becomes Detect Displays and click it.