How to set up extended display win10?

win10 how to set up the extended display? When we do software development, we often need to switch between multiple software, sometimes it is very inconvenient. At this time, put another software on another display, it will be convenient for us to develop. This article describes how to expand the display on Windows 10 notebook.
1, a signal line connected to the notebook display VGA port, opening the notebook display setting, the display shows 2:


2, extended display 1:

3, which If the external monitor appears, you can drag the software on the display 1 to the display 2.

4, copy the screen of the display 1 to the display 2:

5, click the application button, and the screen appears. Confirm the box, click to keep changes, complete the settings

6, set monitor 2 as the main display, click on display 2, check to make it the main display: