Fixate the resistance band somewhere and grab it with both hands. Move your body away from it and adjust your balance. Slightly bend your knees. Move your shoulders down. Pull the band towards your face. Your arms are about parallel to the ground, elbows moving outwards. Move back slowly and with control. Try to only move your arms and not the whole body. I am not doing it very clean here.
Butterfly with Thera Band
Bring your resistance band under tension behind your shoulders. Arms are stretched to the sides. Bring your straight arms together in front of your chest.