How to amend the display options
Go to Settings and then select Display
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You can use the Duplicate/Extend these displays drop down to amend the display behaviour of your laptop, and then you can click Identify to show which display is which. If the screens are the wrong way round then just drag and drop the displays using the Select a display to change the setting for it section of the screen above.
If you would like to amend you main screen then select the screen you would like and then click the Make this my main display tickbox.
If you would like to change the Scale or Display resolution, please select the appropriate display and scroll down to the Scale and layout section, where you are also able to amend the orientation, and amend the related drop down boxes.