2- The Settings window will open up. Click on the link that says Identity to display numbers on the corresponding screens. You will be able to find a drop down menu by the name Multiple Displays. It will have the options Duplicate these displays, Extend these displays, Show only on 1 and Show only on 2. The one you need to select is Extend these displays. Since you want this particular monitor to be set as your primary monitor, you can check the checkbox corresponding to the option Make this my main display.