op('count_down').StartTimer( ammount_of_seconds, run_callback = True )
If you have a specific set of minutes, hours or seconds call
op( 'count_down' ).StartTimer_Delta( hours, minutes, seconds, run_callback = True )
And often you need the time until a certain time of the day. (If the time lays before the current time, it will calculate the time for the next day)
op( 'count_down' ).StartTimer_Clock( hour, minute, run_callback = True )
To just stop the timmer in its track without running the callback use the StopTimer() function.
To stop the countdown with running the caallback use the regular StartTimer function with a length of 0 seconds.