The takeaway is probably the most important part of the swing so use this drill to make sure you have this first move of the swing down right
The one plane swing is the way to go for consistent impacts because the clubface naturally closes on the downswing and does not require hand manipulation to square the face.
Since we are swinging around the body in the one plane swing the club should travel on an arc and not down the target line, thus the right arm gets extended and the left arm bends on the follow through.