I only have to observe the flow of respiration. I do not have to do any labour or exercise. The student feels very irritated with the wandering mind. Do not get angry with yourself, do not get angry even with your mind. Anger is anger after all.
Irritation is irritation.
It will make you very miserable. You have come here to become free from this habit-pattern of the mind to get irritated. Just be aware, At this moment my mind has wandered away. Just accept it. Then start work again in all earnestness.