Jean - If you go to Youtube and look for Treadlelady's channel you will see a quick video demonstrating how to treadle. Also go to
http://www.helenhowes-sewingmachines...totreadle.html and there is an explanation of how to do it.
The only real problem I have with treadling is that I always try and grab the non-existent handle to start off. Much like my friend - I cleaned up a hand machine for her last week, and when she started to sew with it she kept putting her foot down on a non-existent pedal.
I put my left foot nearer to me, my right foot further away on the treadle, and start off by moving the balance wheel with my hand. The hardest thing I found was learning to keep my feet absolutely still when I stopped - the slightest movement backwards can cause the thread to break.