I looked everywhere for this but could not find it so i'm just going to throw out this little chunk of code to help anyone else with this problem.
This is not to say its not out there only that i could not find it.
1.first you need to give your timer button (or another sprite) a Boolean and set it to false.
2.have the thing you gave the bool to become true on the buttons click.
3.then to check if the bool is true, go to you thing that has the bool on it and then choose "is Boolean instance variable set"
4.make a sub-event.
5. in that sub-event, make the timer decrees as fast as you wish.
if any of this was unclear, please let my know and ill fix it.
hope people find this helpful