During meditation, the back should not be leaning against anything. It is a normal
occurrence during Zen meditation for chi energy to draw into the spine and rise
within it from the base up slowly to the cranium. Should the back be leaning
against a chair, this natural flow will be blocked.

The three most important things regarding the correct meditation approach are 1.)
still body, 2.)still breath, 3.) still mind.
Begin by observing the breath. Do not try to force your breath to become calm.
Completely relax the body.

The six aspects of correct breath according to ancient Taoist monk Chi-i are the
following:
long, slow, deep, even, tranquil, and fine. After just a little practice this all settles
quite naturally.
The navel is the “ocean of the breath” and is the primordial essence of life energy
in the human body.
Breathe into the abdominal area. This is a must. Upper thoracic breathing keeps
you “top heavy.”
It can be said that samadhi is characterized by tranquility, a state of mind not
disturbed by external circumstances or situations.
Samadhi meditation is characterized by a singular focus on the experience of the
moment. You recognize this by not being easily distracted by wandering thoughts.

“If you want to accomplish anything in this world,
you must use all of your mind in order to succeed
Therefore it is of utmost importance to practice samadhi
on the profound path of the Buddha.”
——-from the Great Treatise On The Perfection Of Wisdom