Breath as anchor, world as field
Mindfulness does not ask you to stop thinking. It asks you to know when thinking is happening, without immediately believing the whole story. The breath is a humble anchor: it is always here, always changing, never arguing about whether you are doing it right.
One simple shape
Sit in a way you can sustain. Feel contact with chair or floor. Let the spine be long enough to breathe. Then, for a few minutes, rest attention on the sensations of breathing — cool air at the nostrils, the rise of the belly, the pause before the exhale. When the mind wanders (it will), notice, and return. That return is the whole practice.
Why “one field”
Thoughts, sounds, and sensations arise in the same awareness. The world is not outside consciousness and consciousness is not a small thing inside the head — those are useful maps until they are not. You can explore that in your own direct experience, gently, without adopting anyone’s cosmology overnight.