Durst Automatic Timer: how does it work?

I have a DES100 kit and it comes with an automatic timer, I am unsure on how it works. It only has two buttons (focus and expose) and a dial for the time, plus a hidden one wich I believe is for the calibration.
I'm pretty sure I have it wired up correctly but each one of the two buttons does exactly the same thing: the light of the enlarger stays on until you press the button again, so the "timer" aspect of it is pretty much gone

Anyone can help me figure this out?