[Trigger Noob =]]

I'm making a map similar to maps like tree tag and sheep tag. How do I make the timers.
So far I've got this :
E:
C:
A: Countdown Timer - Create a timer window for Timer with title Time left
Countdown Timer - Show (Last created timer window)
Countdown Timer - Start Timer as a One-shot timer that will expire in 1200.00 seconds
I've also tried other ways but they don't seem to work. How do I do it?
:scary