An object that has a create event with a code that says this:
second = 0
minute = 4
timer = 0
the minute = 4: this can be replaced with how many minutes you want
the timer to count down
Now, make a step event, and put this in code:
if timer = 30
if second = -1
Now, draw it with draw commands and there you go!
To make something happen when the timer reaches zero, put this in step in a NEW
if minute = 0 and second = 0
The room restart can be replaced with whatever you want to happen.
Here are some screenshots:Demo of Timer