Find comfort in your seated posture:
Begin by sitting on the floor/mat with legs crossed. Notice the tendency for the pelvis to tip backwards creating a rounded back. Place a meditation cushion or blanket under the sitting bones to provide height and allow the knees to be lower than the pelvis. This will promote an upright or slightly forward tipped pelvis.
Now bring your attention to the stacking of the body - shoulders over hips, head square on the shoulders. Breathe and lengthen through the roof of the mouth and crown of the head. Bring your attention again to the sitting bones and up through the body, lengthening the spine as you breathe. Drop the shoulders and relax the jaw and eyes...breathe...fill the lungs from bottom, to middle to top of the lungs and release the air completely. If you are struggling with anxiety, fear or restlessness focus on completing the exhalation by drawing the navel toward the spine. This will release that last bit of breath that tends to stay in the lungs. As a result, the lungs can fill more completely with fresh air - cleansing and revitalizing the body.
Continue breathing and when throughts enter the mind, notice them and return your awareness to the breath. Spend a few minutes each day practicing seated posture and breathing. Know that you are calming the mind and treating the body to released tension and anxiety and replacing it with a sense of peace.
There's always more to learn about yoga and in turn, learn about yourself.