To practise zazen we sit simply in an upright posture on a cushion called a zafu with our legs in lotus, half lotus or Burmese position. We need a stable base of three points of contact with the ground.
Breathing will regulate itself. Zazen is its own purpose, there is nothing to achieve and no special technique to learn. Once we have been shown the posture, we find our own way. We are just simply and stupidly sitting, fully awake and aware in the only moment that exists in which to be sitting. The past has gone, the future does not yet exist, the moment of experience is all there is. What we think, imagine, remember and project are all stories we tell ourselves in the moment of the present. Zazen not only reveals this to us but returns us to our natural state which is not caught by these abstract realms of thinking but experiences unobscured reality as it is.
We don’t try not to think when we sit but merely witness the colourful activities of our minds despite the fact we are merely sitting still. As Zazen returns us to our original state of simple contentment in reality we simultaneously learn what it is in us that prevents that state. A lifetime of learning about ourselves like this, of wobbling-along, continually losing, seeking and again finding contentment with reality through Zazen is our ordinary life as Buddhists.