[EdZ]

Can somebody please explain to me how to swing with only the left arm ?

I think it was Mathew who suggested this was important for swinging but I just can't seem to get it. I have no control of the club when trying this. Is the left thumb used for pressure behind the shaft ?

In the Tom Tomasello correspondance video he shows this motion of the left arm with an almost acquired motion and it looks so efforltess. I have also tried the double overlap with some success.

To start - swing back with both hands and let go with the right as you start down. It can be helpful to split your grip when doing this.

As mentioned, use a short club/wedge, and begin with chip shots or better, begin with putting until you really get the feel. A great way to learn the feel for PP#2.