From what I've read, you follow basically the same mechanics as without the PT. I think you either count with one hand and push with the other or do the count&chop with one and push with the other.
What should be happening to start the clock is that all officials should be ready to start when the ball is tapped in their area. The timer is also starting the clock with the buttons at courtside.
Personally, I'm against the system
. It puts people like me out of a job
