There are multiple ways you could do this. You could make a boolean attribute called "startTimer," When the button is pressed change attribute "startTimer" to true.
When "startTimer" is true start counting down.
Alternative,
Set your timer to 0.
When you touch the button change the timer amount to whatever number you want greater than 0.
Make a rule that says when timer amount is greater than 0 start counting down.
There are many (endless) possible ways to achieve your goal.
Answers
There are multiple ways you could do this. You could make a boolean attribute called "startTimer," When the button is pressed change attribute "startTimer" to true.
When "startTimer" is true start counting down.
Alternative,
Set your timer to 0.
When you touch the button change the timer amount to whatever number you want greater than 0.
Make a rule that says when timer amount is greater than 0 start counting down.
There are many (endless) possible ways to achieve your goal.