Step-by-step explanation:
When you want to show your presentation through a projector and want the presentation to be displayed on your laptop at the same time, you will simply attach the laptop with the projector using the wire. Then you will start the Slideshow from the menu at the top panel of the powerpoint. Now to display the presentation on the projector and on your laptop simultaneously, you will just need to press the function key along with the F8 key, which is Fn+F8. This will allow the presentation to be displayed on the screen of your laptop as well.