5.Bend at the waist. Bend at the waist, not the back. It is very important that you bend from the waist properly. Bending from the waist will set your hips, back and shoulders all in a straight line. With these three sections of the body aligned, you can properly rotate your hips and shoulders along the same plane. If you bend from your back, your hips, back and shoulders will all be pointing in different directions, making it impossible to rotate consistently.
(from an article titled "How to Make a Proper Golf Stance")
I would like to ask a couple of questions concerning this paragraph.
1) What is the difference between Bend at the waist and Bend from the waist ?
2) Does all in hips, back and shoulders all in a straight line refer to hips, back and shoulders ? (all mentioned parts of your body)