I ordered a new timer and a new knob on-line. I was pleasantly surprised to find the parts on my porch the very next day !
First--I unplugged my dryer from the electrical outlet and then with a Phillips head screw driver-----I unscrewed the top part of my dryer to expose the area behind the control knobs.
Using needle nose pliers -I disconnected the wires from the old timer, removed it, positioned the new timer in it's place and reconnected the wires to their proper ( and labeled ) places.
I reassembled my dryer top with my Phillips screw driver.
Replaced the knob and have been happily doing laundry ever since !