Is it important for a junior to have a pre-shot routine to hit good shots, so teach him one like this
You can either set up to a bunker shot square to the target for a lower trajectory and more roll or open to the target line with your clubface at the target for a higher trajectory and softer landing
Although many players believe that you can either putt on an arc or straight back and through, the putter shaft is attached to the head at an angle so this requires the club to travel on an arc