1) Attach the band safely so that when you grab the resistance band is at your chest level.
2) Step firm on the ground so that your feet are shoulder width apart. If the surface to which you attach the band is low, then drop down on your knees with your knees at shoulder width.
2) Grab the resistance band with one hand with your palm facing forward. Keep your arm extended to your side. Do not fully extend your arm so you don't end up locking your elbow. Keep a slight bend.
Remember to keep your back straight, look straight, chest up.
3) Pull the band around until your arm is a bit past chest. You can stop in front of your chest, but going beyond that will add more strain to the muscle.
4) Slowly return to your starting position.