It’s just a number. Minutes are arbitrary. 7 is arbitrary.
Sit. Sit comfortably. Sit still. Don’t get fancy.
Set a timer for 7 minutes. An egg timer. The timer on your phone. The timer on a watch you have taken off.
Close your eyes.
Fail to notice your breath. Continue to fail to notice your breath.
Have no thought.
Notice everything around you without focusing on anything. Fail to notice yourself.
Keeping having no thought. When you have a thought, stop having the thought.
Keeping hearing and feeling and smelling. Notice but never focus. Allow noticing to flow through you and around you and past you. Avoid focusing on what you notice.
Time’s up. Open your eyes. Turn off the timer. Get up. Move about.
Do this once a day, many days a week.