Nice, big, juicy bite. This is a very good sign for you, Tanguerita. Good karma.
There are several supporting ideas to this that might help, which are not present in Western thought, such as cosmic vibration, or om, ether and prana. Look into "harmonic resonance" and "free energy," which have some Western equivalence. I will try to fill in a couple gaps, but I can't get you all the way there, as my words will not be enough.
Fast and loose:
It all starts with OM, which is The One and only, ever-present cosmic vibration. Om has no end or beginning, it goes round and round and just...IS. Then there is Ether, which is the infinite, subtle universe: everything that is, is not and has yet to be.
Ok. When Om strikes this Ether, it (the Ether) begins to resonate that vibration, like an overtone? Much like the strings adjacent to one struck on a piano or violin, or like the rattle of the windowpane when a big truck goes by. That "resonance" of Om is Spirit. Like all vibration, it has movement, rhythm, duration and direction, going back and forth, up and down, out of which is born dimension.
Now then, there exists a "potential" within that dimension, a kind of "harmonic resonance" out of which form and structure are manifest: force, energy, matter, etc. (the gross universe if you will). "You," your life, your mind and senses are the result of this harmony between Om, Ether and Spirit (or Brahma, Vishnu and Siva, or The Father, Son and Holy Ghost). Your matter, your gross body, your energy, your form and structure, are defined by the quality of that harmony (your Spirit): from perfect harmony to disharmonious, good karma/bad karma. You see?
The aim of yoga is to "tune," if you will, your mind and body to optimally resonate the vibration of om, over which we have some control. That's it. In other words, yoga provides the potential to structurally alter and improve that harmony and therefore that resonance of om, which is The (Holy) Spirit.
That's the elephant in a nutshell. I know it's not a complete answer, but I hope it helps. Here's an artwork that says it all much better than I can.
The next step is how the "spirit in matter" is continually reabsorbed back into om and re-manifested with less or greater resonance, or Spirit, based on the laws of karma. Yahoo! But maybe someone else will take a crack at that one.
peace,
siva