How to use a projector with a computer please?

I do some "suitcase" instructional courses with a laptop and projector. Most good projectors have a VGA "in" and "out" port...you connect the laptop VGA out to the projector "in" and the projector "out" to the monitor. This allows me to watch the monitor while facing the class.(its proper etiquette not to turn your back on the class!) Some projectors have a "bypass" button so you can turn off the projector to the big screen but the monitor stays on..so you can keep the class attention while changing the presentation without them seeing a bunch of changing slides that would detract from the class. Some projectors have a "remote'' that changes the slide among other things. I use a wireless mouse on the laptop so i can use the "pointer" and not have to turn my back on the class.