How to get dual screen setup for Laptop

First thing you will need is a VGA or a HDMI cable.
Then

1)Connect the cable to your external display and the other side of cable to your laptop.

2)if everything goes right and your screen flashes a time then go to your laptop settings>display settings and there you will have option of MULTIPLE Displays.Click on that and select extend these displays and hit apply.

and there you go.

Enjoy:)