Resisted shoulder external rotation and horizontal abduction in supine

Lie on your back with a resistance band in both hands.
Bend your knees and place your feet on the ground.
Tuck your elbows on your side and stretch the resistance band to sides and hold.
Return to the starting position.
Now, raise your arms towards the ceiling so that your hands and shoulder joints are in vertical position.
Stretch the band to the sides and hold.
Return to the starting position and repeat.