Stand against a wall. Push your low back into the wall (walk your feet out as much as you need to keep a connection between your low back and the wall)

Create a W-shape with your arms. Your shoulder blades, elbows, wrists, and hands should all be touching the wall.

Slowly extend your arms into a Y-shape keeping all the same body parts against the wall.

Squeeze your shoulder blades down and back the entire time!