Imagine that the name is a force being channeled down from your Kether (and from G-d/Brahma/The All etc.). Now imagine that the force flows straight down through your pranic tube until it reaches your feet. (Some people stop at the heart and even try to write the name there in glowing white letters). You can try to inhale the force while imagining/projecting the letters of the name being vibrated in front of you if you wish (In the case of Hebrew names, you'll have to know what they look like in Hebrew letters). When the name/force reaches your feet, expel it from you while pronouncing it in a humming/chanting way so that it causes your body to vibrate all over. THE SOUND OF THE NAME SHOULD BE THE ONLY THING IN YOUR MIND WHILE YOU VIBRATE IT. You'll have to experiment to see what pitch and tone works best to cause this vibration to occur. You may have to use a lot of air. If you really can't do this due to sound restrictions (you're not alone in the house/room etc.) then a forceful whisper will be better than nothing so long as you're visualizing the energy and force. After a while, you should be able to vibrate a name and have it vibrate specific parts of your body. Some say that if done properly, the practitioner should break out in a sweat much like in Yogic breathing exercises and have trouble standing at first until he/she gets more practice.
My point is one of comparison here, and I've only reproduced a couple sentences of the text that I felt were necessary as guides to paraphrasing. For anyone interested in expanding the reference section of their personal occult library, I would recommend purchasing the book since it is full of useful exercises and information explained in an easy to understand manner. However, the ceremonies themselves are of questionable value, being nearly impossible to perform adequately by a beginner.
"Certain names or Words of Power when properly vibrated or intoned attract certain energies which are associated with them."
This is an important thought to keep in mind. Words have power when used properly, paying attention to pitch, tone, and imbued with intent.
In the past, Hermetic initiates (Egyptian/Hellenic-influenced traditions from the first centuries of the common era) made use of what are now referred to as barbaras names/words of power, which were symbolic words wherein each letter/sound was representative of a particular type of magickal force i.e. zodiacal, planetary etc. Programming one's self to associate specific forces and/or states of consciousness with particular sounds and/or letters, and then vibrating a symbolic word that makes use of those sounds/letters would be a highly effective method of invoking (a conglomeration of) forces during ritual. In some ways, it's a sort of magickal shorthand, since you're using a word to instantly summon a potent force (or collection of forces) rather than having to go through all the repetitive preperatory work to call each one individually right then and there and thus spend additional time and energy during ritual. In essence, all the hard work would have been done in advance to save time later.
There's still a lot of hard work involved in programming an effective word of power in order to make it effective. My point in mentioning that is to emphasise that you're still going to do the work of invocation of individual forces regardless, but putting them into a trigger word form just helps to save time later during ritual or whenever you need to call forth that force (or collection of forces) on the spot and don't have time for a ritual.
"The student should first imagine a glowing white Light above the head..."
To make a long story short, the Ciceros have you visualize your Kether first, and then visualize it descending down to your heart or Tiphareth center. They then mention that the letters of the name that you're vibrating are to be imagined in white letters within your heart or Tiphareth center. The name is then pronounced very slowly so that the sound vibrates the entire chest region and then felt through your whole body. You should imagine that the sound of the name is traveling to the furthest regions of the universe (and to infinity). The Ciceros mention (in accordance with other authors on the topic) that the "Vibratory Formula of pronouncing names" usually produces a sensation of slight fatigue and exhilaration when done properly. They also mention (again in accordance with G:.D:. tradition) that only divine names are to be vibrated.
Personal recommendations and observations
I agree that only divine names should be vibrated, as any force that is invoked can potentially leave some residual energy/effects behing in your aura. Beneficial side-effects are always better than harmful ones.
I find that full or regular volume vibration of names is best. A forceful whisper, while being better than nothing, isn't nearly as potent in comparison. I've noticed that a slightly nasal tone is the most effective for me. My breathing is smooth and relaxed all the way through the name, and the force or oomph comes mostly from my gut or solar plexus region. The volume isn't overly loud or strained; it's medium-loud speaking level. Due to the force coming from my gut, the pitch is sometimes slightly lower than my regular speaking voice (though not always - see below). My mouth is usually not full wide open, and my throat is NOT in a proper singing position e.g. as though I am yawning. In fact, I find that a smooth, round singing tone is far less effective for me when vibrating names. A semi-closed mouth, nasally, deep but relaxed straight tone (with no vibrato) pronounced slowly with confidence seems to produce the most obvious energy effects.
I've noticed in my practice that there's a similar action between a musician's drawing of a bow across the string of a cello and the vibration of a word or name. In the same way that a cello string will have a very slight delay before it reaches full volume, there's usually (for me) a slight delay between the time when the word comes out of my mouth and when it reaches full potency (usually while sustaining the last syllable of the word). During regular performance of the Lesser Ritual of the Pentagram, for example, I almost always observe that while I sustain the last syllable of a divine name, the pentagram I'm charging starts to shimmer in front of me, and then radiates waves of force in all directions around it (with the centre remaining still but becomming stronger/more solid).
I like to imagine that the force of my voice creates an energetic friction in the air of the room in the same way that the friction of a violin or cello bow causes a string to sound.
Also, I've found that some names require either higher or lower pitches to be used in order to come through most potently. Higher spiritual names seem to work best with higher pitches and tones that vibrate/stimulate the top of the skull or crown chakra area. More dense or earthy forces work best with lower pitches and tones that stimulate lower parts of the body.
Matching the pitch of the room is a good rule of thumb if you can't decide what pitch to use for a particular name. I usually feel prompted to use specific pitches, but often the most effective pitch will end up being the one that causes sympathetic vibration to occur within the room. If you're not sure what I mean by this, then a simple experiment in a small tiled bathroom will quickly clear things up. Go into a small tiled bathroom - the more echo the better. Then sing a long tone while slowly raising or lowering your pitch until the whole room seems to resonate at the same pitch as your voice. You should notice that at one particular note, your voice sounds louder than normal and that the whole room resonates at that same pitch. You'll probably feel that note vibrating the whole room and everything in it right through your own body.
With practice, you'll develop an intuitive feeling for which pitch to use to match the divine name and room you're working in.
Maintaining a relaxed, confident state of mind that permeates your whole body will help tremendously if you're having trouble learning to vibrate a word effectively. Any feelings of self-consciousness or doubt will hinder your effectiveness, so cultivate that relaxed, open, and comfortable state of mind first.
When charging talismans and using name vibration to invoke divine forces into the names inscribed upon them, I can tell when the proper force has been tapped into and drawn down into the object by whether or not a sudden flow of (higher/divine) energy can be seen rushing down into the talisman (and particularly around the area of the name being vibrated). In the case of Hebrew Angelic names, the flow I'm looking for often starts with a few vivid blue sparks followed by a clean-feeling whitish etherial substance. (This can be seen clairvoyantly moreso than with physical eyes.)