How do I make timer functions

Hi friends,

i am having quite a pickle with adding a timer function on my game.

the goal is when my player sprite collides with a boost sprite, i will be calling a timer function. so that the boost will wear off at a given time.

i'm trying to achieve same effects in temple run when the player gets boost and the boost wear off some point in time.

thanks in advance

Attached is a 24 hour example, but I modified it to show you a simple second countdown. Use arrow keys Right and Left to pick up boost.