On your keyboard you should see a key labeled Fn. Holding it down and pressing
one of the function keys should modify what shows on the projector and what
shows on the laptop. On a Toshiba it's Fn + F5.
What is the make and model of your laptop? Someone else here probably has the
same machine and can tell you what key combination you need.
Okay, if you go to Slide Show > Set Up Show and set the slide show to display on
the secondary monitor, i.e. projector, you should be able to see both views when
you toggle to projector and laptop on the keyboard.