Preparation - Beginning ...
Pivot right heel, cat stance left, hold circle right hip, step with left ...
Your left hand goes up (leading with the thumb) and your right hand goes down ...
You visualize a small bird in/on your left hand; it takes off and your hand raises up gently beneath it and you right hand (which is 'high' and palm down holding a circle on the right hip)... travels a little forward and then in an arc downwards to finish (just for now) along side your right hip.

Grasp the Sparrows Tail - Ward Off Left (facing north)
Grasp the Sparrows Tail - Ward Off Right (facing east)
Grasp the Sparrows Tail - Rollback (facing southeast)
Grasp the Sparrows Tail - Press (facing northwest, going forward)
Grasp the Sparrows Tail - Withdraw (facing northwest, your arms moving backward)
Grasp the Sparrows Tail - Push (facing east)
The next posture (Single Whip) faces you towards the west

This is the sequence that begins the Part One of the Long Form, follows 'Wrestle Tiger Return to Mountain' at the start of Part Two and Three and regularly repeats throughout. It is so intricately interlaced with the whole form that to the regular practitioner it becomes a familiar friend with a certain character and form of its own. This sequence is a form of sorts in its own right, yet when performed as a part of the whole it all but vanishes. To the practitioner, that is, one who practices;this little sequence within a larger sequence is performed so often that the practitioner may attain through that practice the high level of proficiency that is "doing it without thinking about it". The same applies with Preparation - Beginning. Of all sequences this one is sure to be the most practiced, therefor (and at this end of the process) the least thought about.

Satisfied and Surprised!
Newcomer's come expecting all sorts of things from Tai Chi. Many have expectations of 'weird' physical sensation. I don't knock this, it is understandable and indeed I would suppose that 'connecting' with some other power (able to leap tall buildings with a single bound etc.) was one of the things that I hoped for from Tai Chi, maybe even yearned. I suppose that was so, but I have forgotten now. My observations since is that those who expect the most are always the most disappoint, and those that practice are the most satisfied and surprised!
For those that practice the first surprise and/or weird sensation is that following proper Perpetration and an appropriate period of calming - the hands/arms seem almost to 'rise' themselves with no conscious effort on the part of the practitioner. The visualization associated with 'Beginning' is "the Sun rising slowly above the horizon" and the purpose of practice is to train the body to react instinctively and without thinking or at least without calculation of gain or loss. The Sun comes up, the Sun goes down. The Moon comes up and the Moon goes down. That's it! No calculations are really necessary to the Tai Chi practitioner. Other calculations, theories and equations may be important to people involved in other 'walks of life', but such contravenes are unnecessary vexations to the Budoka.

The form (as much of it as you can 'remember' - without thinking about too hard) ought be practiced so often that to simply stand in 'Preparation' for just a few moments is enough to instigates some kind of a sub-concious process of calming, centering or settling. There really is nothing metaphysical or cosmic about this process that is perfectly able to be the cause of physical and emotional sensation - and these practices are the bed and table of tried, tested and established elements of most meditation practices.
It has long been of assistance for meditators to follow some routine, to settle into exactly the same posture every time. Some don the same robes or cloths every time, some always face in the same direction or at the same thing and so on. In most cases where there is purposeful intent to meditate, incense is burnt and ritual is either created or followed. Attention shifts from what is here to what is not.

Meditation
Those preparation's just mentioned are not in themselves 'meditation', yet they are vital aids to 'set the tone' or get you in the mood. Trivial aids set low aims yet complicated rules are impossible to follow. The Middle Way is recommended and in Budo Martial Code the phrase that points to this is (simply) "Walk the Path" (Do not yearn to be on some other path).
To those less practiced in meditation the use of incense and so on as precursor is valid as that - cue or prompt, however, the meditator is advised to remain alert and does well to remember the Zen adage that "When the finger points at the moon; contemplate the moon, not the finger".
Ultimately those who diligently practice meditation may (if they so choose, some choose not) dispense with any or all aids and simply 'meditate' upon or 'in' whatever is [any conditions].
Sparseness or doing without/simplicity is not uncommon in many cultural, spiritual and religious practices. The excess of the most opulent and wasteful are well known, but so too (for the opposite reason) are the simple ones. The prominence of Zen and Taoism in Budo Martial Arts practice must be recognized as highly influential. Between them (noting also that they are each product of different times and separate cultures) Zen and Taoism effectively cover the extreme's of nonchalance and hostility with regard to "outside form".

The visualization of 'Beginning' sequence is 'the sun rising above the horizon'. Your hands are thus 'lifted' and it is suggested that you "set a higher goal".
For the Grasp the Sparrows Tail sequence the first visualization is that as the small bird alights from one hand - the other grasps or strokes it's tail as it fly's upwards and away.
'Beginning' is the first and last therefore the one and only time within the whole form that weight is distributed evenly between the feet. This posture signifies connection straight up and down - between Heaven and Earth. The next, 'Grasp the Sparrows Tail' signifies the more complete connection diagonally between left and right, bottom and top. As the sequence unrolls the practitioner is familiarized with the cardinal directions of north, south, east, west - with just one brief look over right the shoulder (Rollback) to where the Tiger rests.

The repeats of GST throughout the form is in effect just like the main theme of a symphony, or if you wish the catchy chorus of this weeks number one! Either way, each have been crafted to be memorable without the aid of a name of their own; and if you can hear one of those 'hooks' in your head right now you have instantly proven yourself to be a certain kind of connector of Heaven and Earth.

Of the nine performances of this sequence within the three parts of the whole form; six are 'Short' therefor metaphorically branch off there at Single Whip; and the other three are 'Long' therefore the sequence does not end until Wave Hands In Clouds and Side Single Whip have also (in that order) been performed.

Words and phrases not compatible to Tai Chi have been used here and indeed it is an accepted matter of fact that as far as Tai Chi is concerned words only confuse; and the more the words, the more the confusion. I have instantly proven that!

The Ancients had it that the sequence of postures and the associated 'visualizations' of any and all Tai Chi Form ought not ever be written down. Time has eroded that ideal, but Tai Chi is not unique in its need to adapt to this changing world.

Before you right now is "me talking about Tai Chi", this time using the web; one of the thousands of 'new' novel and challenging ways of getting in touch with each other that technology unrolls endlessly before us these days. None of these new fangle tools of communication should really compromise or threaten Tai Chi anymore than all that has gone before, because like before, they make no difference or have no effect upon the 'spirit' of Tai Chi which exists far beyond words and closer to visions.

Tai Chi is riddled with 'visualizations'; there are thousands of them, but the only one that will work is yours. Try to not confuse the issue with words that mean nothing.