When you are ready, it will come. There will come a time when your Qi will talk to you. Not verbally of course but just as good. It will talk to you via your own body and the movements that you are making during your 'Waving Form' practice.
There will only be one way that you will be able to perform your Taijiquan Waving form, all other ways will feel not quite right. You will HAVE to move your arms and hands in particular in a certain manner and at varying speeds in order for the external movement to emulate the internal. You will find that the movements will begin and finish at exactly the right time and in harmony with the Qi flow.
Movements like 'Lu' or 'Roll Back' will take on a different meaning and you will gain so much from just that particular movement. The arms and hands will begin to move all by themselves, seeming to just slot into their own particular space in time. Your Qi will cause movements to change so that they emulate the Qi flow much more accurately.
The Kwa is the Key:
If there is any great secret to the Waving form, then it has to be that the Kwa's are open much more than in any other form. For instance, in the posture of Lu (Roll Back) your palms will become parallel causing the left and right axilla kwa's to open greatly. This in turn will cause your movement to become even more in tune with your own Qi and make each movement much smaller.
Your Qi will tell you that you must only make ONE movement during the form and it will begin telling you about postures such as those from Roll Back through Shoulder Press and into Stork Spreads Wings. Then as your form gets even more in tune with your Qi, this will advance to include Brush Knee and Twist Step and eventually the whole form is done where there is no differentiation between postures, only one long flowing movement.