You will require someone to assist you with the exercise.
Lie on your back.
Your assistant should support your forearm and wrist.
Your elbow should be bent and your forearm pointing to the ceiling, starting with your wrist straight.
Holding your wrist with one hand and using the other hand to stretch your hand and fingers your assistant will slowly move your wrist and fingers into a bent position.
Join in with the movement as much as possible.
Hold the position for a moment.
Only move within a range that is comfortable, it should not be painful.
Slowly return back to the start position.