For tubeless set-up, it is recommended to inflate your tires to 3 bar / 43PSI once during assembly. This way the tire can seat onto the rim properly. As a general guideline, you should run your tires at about 2 bar / 29PSI. Of course, the ideal air pressure varies depending on the rider's weight, the type of tire and terrain/conditions. Since most of the rider weight is in the rear, most riders prefer a slightly increased PSI in the back. Please always adhere to the maximum air pressure recommended by the tire and rim manufacturer.
If you're running tubes a higher PSI is generally required to prevent pinch flats.