One of the wonderful things about pedal steel guitar is that the pedals and knee levers can be configured in an almost infinite variety of ways to suit an individual player's style and preferences. This can also be an obstacle for those sitting in on another player's guitar -- the strings may be tuned differently, or the pedals and knee levers may do different things to different strings. Still, it can be done and many well-known players are adept at sitting behind a strange guitar and playing seemingly without effort. It takes experience and a thorough knowledge of one's own preferred tuning, and knowing exactly what each string pull does.
The links below provide a sample setup for S-10, D-10, and S-12 (Universal) guitars. If you are just beginning on steel, use these samples as a starting point. There is a also a blank chart you can download for use in experimenting with your own customized setup. Right-click on the link and save the blank chart to your computer. Then, open the RTF file in any word processor and modify as needed.