Using a pully machine in the gym (as shown in the image) or a long rope with a partner supporting the other end squat down gently and pull the rope towards. One pull with each arm is one repetition. Repeat for the number of sets and reps indicated.
You can modify this exercise to a static exercise where you squat down and pull a rope or towel against a partner, similar to a mini tug of war. In those circumstances pull against your partner for the duration indicated by your clinician, rest and then repeat for the number of sets stated.
Do not tense through your neck and jaw. Place the tongue on the roof of the mouth to activate the deep neck flexors and as a reminder to not clench through the jaw. Make sure to read the additional instructions on this protocol to understand if you are to complete this as a dynamic or static pulling exercise. Ask your clinician if you are not sure.