countdown timer help!

countdown timer help!

now i need help with making countdown timers ive tried but i still cant get it.

action - start (last started timer) as a unique timer that will expire in x sec.
then set a variable : set timer) = (last started timer)
now create a timer window: create timer window for (timer) with title ...
set another variable: set (timerwindow) = (last created timer window)

now create a new trigger: (timer) expires
destroy (timerwindow)
all your other action

it's simple