In order to strike the ball first, it is important not to move off of the ball and to stay centered while pivoting mainly from the waist up. What they now call stack and tilt is just a restatement of a center based swing.
Tilt less for mid to short irons, more for long irons and woods but in all cases no sway and good shoulder turn.
I like ball position a few inches inside the left heel then just widen or narrow the stance depending on what club is being used.
The hands stay ahead prior to impact to create lag.