in the shallow-end, hold the noodle with close grip and keep it in the water. Keep your feet hip-width apart and straighten your back.
Push your arms down and squat until you put your shoulders in the water. Bend your legs and move your arms up again to return to the starting position. This exercise is better performed in waist-deep water for bigger range of motion.
Inhale as you move your arms up and exhale as you push down.
Use your shoulder and tricep muscles to push the noodle down.
Tip: start with small and slow movements and gradually increase the speed and the range of motion as you feel more comfortable.