Set up the display for multiple monitors in Windows 10.

• Right-click in the desktop and then pick: "Display settings"
• Assuming the "Display" tab is selected at the left, scroll down to: "Multiple displays"
• Click the "Detect" button.

 
 

Addendum 11/27/2018: At the "Multiple displays" dropdown list you may need to pick "Extend these displays" to get this stuff to work.