I don't have any experience with it, but remember reading some on the forum here. I think you press the unlock (or lock button, can't remember) button three times. On the third push, you hold it for three seconds. The car will beep and then start.
I think I also read somewhere that when you open the door, the car turns off, so you have to re-start it again to drive. There may be a difference in how it works though depending on whether it's factory installed or dealer installed.