Only do first exercise demonstrated in video unless otherwise instructed

Make sure your upper traps stay as relaxed as possible by keeping the neck long and not shrugging your shoulders upward

The focus is on squeezing the shoulder blades together as much as possible, not how much you pull the band.

Stop your arm movement once your elbows are in line with your body. If your elbows go behind you, your shoulder is likely going to be pushed forward and other compensatory muscles will be working instead.