Take a shoulder width leg stance, take a dumbbell in your right hand and place it supinated near the shoulder, let your elbow face down and slightly to the side. Take a step back with your right foot while your pelvis is still facing forward. Take little air (abdominal breathing), and hold it while keeping you abdominal wall really tight. Imagine someone wants to punch you in the stomach and get ready for it. Keep it that way.
Movement up and down
Start lifting the dumbbell keeping your forearm vertical. While extending, rotate the arm right (like a spiral). If the weight is challenging, feel free to bend left a bit and tense your glutes, legs and abs. That will help you raise it. Keep the weight up in the final position. If you are feeling a lack of air, this is the time to take a breath, then tense your abs and start going down. Take it down following the same path.
Repeat the exercise with the other arm, following the directions symmetrically.