How to stop timer?

I got a small problem butt can't solve it im stuck in this and ask for your help! I got a timer function it decreases the time now i want to stop the timer when it reaches zero, i got this time attribute and stop(effect). and i got this IF TIME <=0 stop time but it wont work

To stop your timer you need a boolean attribute that will only let your TIME attribute decrease while such boolean is true. You also need to change it's value to false when your TIME is equal to 0.

tnx