To start, people should

Bend at the waist and let the affected arm hang down perpendicular to the floor

Relax the arm and shoulder

Bend the knees slightly

Then they should

Slowly swing the arm from side to side, from back to front, and in circles clockwise and counterclockwise

Shift body weight from foot to foot in the same direction that the arm swing

Gradually increase the range of the movements as can be tolerated

These exercises should cause only minimal pain. People should do each exercise twice in one set and do several sets each day. These exercises are done even if the arm is in a sling or in a sling and swathe (as it usually is). Moving the bones in the shoulder joint helps prevent the joint from becoming stiff.