Grab a resistance band with about a shoulder-width grip. Different resistance bands have different amounts of tension, so you may have to adjust your hands closer or wider based on how strong the band is.
The band should not have too much slack in it if any.
Hold the band out in front of your face with your elbows slightly bent.
From this position, pull the band apart, and then slowly bring the band back to the starting position. Don’t let the band pull you back in. Have control.
Focus on using your rear deltoids. Your elbows should remain up and slightly bent throughout the movement, don’t let them drop.