Sitting still is a workout. Your mind will fight it like the last rep.

Stillness is uncomfortable because the mind is used to being fed and does not stop asking when the feeding stops. The restlessness that arrives in the first few minutes is not proof you are bad at this. It is the actual work, the same way the hard part of a set is the hard part.

Sit for five minutes with nothing, and let the urge to reach for something come and pass without acting on it. Do not aim for calm. Aim only for staying, and notice that the restlessness peaks and then drops on its own.