Maintaining your posture in the backswing is key to maximizing power and accuracy. Linking your arms and club in front of your chest allows the club to swing on the correct arc and plane angle.
Setting up with arms crossed on chest, bend forward from hips until shoulders are over toes, add some knee flex.
Maintaining your posture in a centered turn requires the spine to move from forward bend at address to left side bend at the top, returning to forward bend at impact to right side bend on finish.
To accomplish this, the shoulders turn perpendicular to spine (left shoulder turns under chin) then hips turn parallel or same tilt as shoulders (right hip turns back and up).
Legs move in response to hip turn. Depending on the amount of hip turn, the right leg will straighten and the left knee and hip will go down.
Check out the video below. Depending on flexibility, the hips will turn the correct amount needed to reach full shoulder pivot at top.