Windows 7 & Windows 10 are easily configured to add a second monitor. When using a second monitor an extended desktop allows users to benefit from additional working space. Users are able to work across multiple programs simultaneously.
Press the Windows logo Key + P.
Select the Extend Option
Right click in an empty space on your desktop & select Screen Resolution.
Select the drop down by Multiple Displays. Select Extend these Displays.
Press the Windows Logo Key + P
Right click in the empty space on the desktop.
Select Display Settings.
Scroll Down to Multiple Displays
Select the drop down and select Extend these displays.