The first line is the target line, through the ball to the hole. Then I draw a line at 45 degrees to that line. That's for the stance, which is open, and my toes are on that line. The shoulder line falls somewhere between those two lines. The clubhead is pointing down the target line.
Most golfers square up and take the club back low.
What you want is for the club to be quickly up and steeply down. You'll have a rectangle about the size of a dollar bill. There's another way of practicing this concept. Put a second golf ball about eight inches behind the ball you're trying to hit out of the banker. If you take the club back too low, you'll hit the second ball.