Summary
You can connect your laptop to the projector by using the cables provided on the lectern. Classrooms may include a VGA cable or HDMI cable, and some rooms will be equipped with both. There are a number of options for display when you connect your laptop which can alter what you and your class do and do not see.
Body
1. Press the Windows key 
+ P on the laptop keyboard.
2. A pop up menu will appear on your screen with a number of options;
Computer Only: Image will only display on the laptop screen
Duplicate: Image will display on both projection and laptop screens.
Extend: This will cause the display to treat the projector and laptop as two different displays, much like a two monitor set up in an office.
Projector Only: Image will only display on projector screen.