This passage by the Siri Singh Sahib, Yogi Bhajan appeared on page 185 of the “Mind, Mantra and Meditation” section of the book,  The Man Called the Siri Singh Sahib, which was published in 1979:

Sit in easy pose.  Place the palms flat together at the center of the chest, thumbs touching the center of the sternum.  With the eyes closed, focus at the third eye point.  Inhale deeply, concentrating on the breath.  On the exhale, slowly chant the mantra in the Law of Seven, The Law of the Tides, i.e., vibrate Sat in six waves and Nam as the seventh wave.  Thread the sound through the chakras, beginning at the base of the spine and on Nam, let the energy and sound radiate from the seventh chakra at the top of the head, out through the aura. 

As the sound penetrates each chakra, gently pull the physical area it corresponds to.  The first center is the rectum, the second is the sex organ, the third is the navel point, the fourth is the heart, the fifth is the throat, the sixth is the brow point, and the seventh is the top of the head. 

If you can build this meditation to at least 31 minutes 6 seconds per day, the mind will be cleansed, just as the ocean waves wash the sandy beach. 

This is the beej (seed) meditation.  Beej mantras such as Sat Nam are the only sounds which can totally rearrange the habit patterns of the subconscious mind.  We all have habit patterns; we could not function without them.  But sometimes you want the patterns to change.  By vibrating the sound current Sat Nam in this manner, you activate the energy of the mind that establishes and erases habits.  Consequently, this meditation is good to do as an introduction to Kundalini Yoga.  It will open the mind to new experiences. 

Chanting this mantra seven or more times totally balances the electro-magnetic field of the body.  A long-time student will still mediate in this way, particularly to clear off the effects of a hurried day before beginning a deep meditation.  After you chant this mantra, you will feel calm, relaxed and mellow. 

” When you love somebody, what do you do?  Don’t you call his name or her name all the time?  Is it true or not?  When you love somebody, you like to call the name of that person.  If you love the Truth, then you will call Sat Nam.  When you call Sat Nam, everybody knows you are a “Sat Namer”.  You become identified.  And when you say Sat Nam, it means you are Truth” (February 14, 1972) 

“Everybody talks about liberation.  The fact is, we are liberated when we are not a slave to any negative habit.” 

Here are two recordings of Sat Nam to listen to: