Rearrange your displays
You'll see this option when Windows detects more than one display. Each display will be numbered to help you identify them more easily.
Identify a display
To see which number corresponds to a display, select Start > Settings > System > Display > Rearrange your displays, then select Identify. A number appears on the screen of the display it's assigned to.
Detect a display
If you connected another display and it isn't showing in Settings, select Start > Settings > System > Display > Rearrange your displays, then select Detect.
Arrange your displays
If you have multiple displays, you can change how they're arranged. This is helpful if you want your displays to match how they're set up in your home or office. In Display settings, select and drag the display to where you want. Do this with all the displays you want to move. When you're happy with the layout, select Apply. Test your new layout by moving your mouse pointer across the different displays to make sure it works like you expect.