Just sit in your comfortable position. Remember if you sit on the bed (Zazen position) you must sit on oblique angle. Try to listen every sound as you can, no matter how loud or how subtle they are and reply from your mind as you hear a chirping of a little bird, ” I am hearing the chirping of a little bird”. As you hear a muffled sound of construction then say, ” I am hearing the muffled sound of construction”. And doing this at one stage you will able to lost yourself within the circumstance. Now make your self more relax and concentrate on your many different parts of the body as its pertains. And finally you could soar in the sky or go back to any kind of past phenomenon what you had experienced before or any incident that your thought take you, in this case you must follow your mind and remember don’t intercept in your thought.