A timer in Keynote

I am learning how to use Keynote. I would love to insert a timer on some of the slides.

When I go to Inspector>Slide Inspector>Start Transition>Automatically, I can see the option to set a specific time for the slide to play but but:

*I need a visible timer on the slide
*I need it for 5 minutes minimum

Is it possible, do you know?

Thank you so much for your help and feedback,
Linda

Message was edited by: lindacamurato

Message was edited by: lindacamurato