How to display final time at the end of a game.

Hello, I am making a short game where the player is to jump and collet pieces of paper. It is a timed trial for them to grab all of the pieces of paper. I would like to know how to have the timer start the second the first object is picked up, and how to stop the timer and then tell the player what time they completed the task in. Thanks in advance for any help
.flowlab.io/game/view/580219