PTO does not work

I own a Toro Wheel Horse 16-38 Lawn Tractor. While I was engaging the blades something snapped and the PTO handle became free with no tension, How do I go about finding the cable or spring that may be broken. I looked on YOU Tube , and found nothing about this problem. Please help, I am 90 years old and don't see real good, but I can follow directions and get things done.