In general there is no deeper knowledge necessary to operate a laser projector in a physical sense. However, laser light may be quite dangerous if it is not properly used.
Due to the coherence of the laser light (same direction and wave characteristics of the light - different to normal light sources), the very sharp rays can be dangerous to human eye or immission sensors.
However, if you respect you local laser safety regulations, it is possible to make a safe laser show.

The regulation IEC 60825-1 is internationally valid and provides information about laser safety terms. Most countries refer to that regulation in context of laser safety.
However, some countries may have much more fear of the "laser mystery" and thus may have stricter regulations.

However, the responsibility for laser operation is with the actual operator. So being careful is most important.

Some things we recommend to respect:
- never shoot single beams to the audience. You may shoot them above their heads (min height 3m) as strong as you like.
- use a safety shut-off option (button etc.) to be able to switch of the system, e.g. if somebody tries to manipulate the lasers during operation or if somebody enters the laser safety area
- keep people under age away from laser devices
- familiarize yourself with laser safety prior to operation. Some countries (very few only) may need a Laser Safety Officer on site during operation

Laser projectors are not dangerous themselves - the danger always comes from improper operation.
 

The following video explains how to safely setup a new show laser device: