In a nutshell ... setup with the front wrist flat and the back wrist bent in a bit and that "shape" is maintained back and through. I feel both hands with equal pressure holding the shape as the shoulders take the club back (a little) and then the body brings the arms/club right back and around to the left (right hander). It will feel like your "dragging" the shaft (with wrists holding the shape) through impact around to the left. If you're having difficulty then the wrists are not holding firm enough or the body is not doing its job rotating and the hands are taking over.
It is best to start with little pitch shots, and just feel the shoulders move (backswing), then the body unwind (downswing) and nothing changes with the wrists from your original setup shape. You may want to exaggerate the flat (or even bowed out a bit) front wrist to help hold. One other crucial factor in holding that shape, is that the pad below your little finger on the front hand is on top of the shaft... can't be off to the side. Watch the "Grip" video if needed.
Move Less ... Get Good! DUPLESSISGOLF