prana and vayu are 2 names used interchangeably referring to the same energy.
Vayu manifests as prana and its subtle forms called:
1.Udana-Our creative expression, upward moving spirituality.
2. Apana-The manifesting current into the world. Elimination and detoxification.
3. Samana-The equalizing force of the universe.
4. Vyana. The outward circulating force of the universe.
5. Prana-the vital force of all creation.
The ascent up the chakras is the path of enlightenment. The decent from the crown chakra down to the base of the spine is the path of manifestation. Together the ascent and the descent comprise the path of liberation.
the yogi works with these 2 currents ( prana, apana) to balance them in the center nadi, or shushumna. there are 3 main nadis. ida, on the left side referring to calm, female, manifest active etc. pingala on the right, which refers to male, unmanifest, inactive, etc. there are many other descriptive words that work. they are representative of the duality of all reality. if we observe in all things our mind plays the trick of duality.
the goal is to balance prana and apana so that the energy of ida and pingala can start pouring into the shushuma which is the central channel, the channel where the chakras reside. this is when maha- kundalini can arise within us because of the balance our dual nature into unified nature. then kundalini, also known as shakti can transmute our attatchment desires into our desires to become liberated.
the source of both is desire, desire is neither good or bad but how we choose to work with desire is the trick. kundalini practice is just the way to transmute desire from working against our mind so that we have to fight against it, into working with our mind because our soul and mind have the same goal, unifying our goal to reside in absolute bliss of oneness.
some of the applicable techniques for achieving this is all of the pranayams reffered to in the great yoga manuals such as patanjali yoga sutras and hatha yoga pradipika. most commonly known for this practice is kapalabhati , or rapid diaphram breathing in which ( with the right state of mind) will forceably push the prana into the shushumna and heat the body so that kundalini can awaken.
other practices include visualizations, bhuti shuddhi, pure intention, and anything else which is creative and oriented towards the goal.
yoga is intuitive
remember yoga is intuitive and when you allow your intuition to guide you you are in yoga. yoga means union. union of our individual or "jiva" consciousness, with the creator consciousness"atma" or "brahma".
when you are in creation you are in yoga. so the trick is to see the practice already here. and bring it close to i-now-ness. so whenever you are concentrating you are meditating. whenever you are moving your body you are practicing yoga. so if you designate a time to stretch and move that is your yoga class. and you will find that eventually the universal mind speaks to you and shows you how to move. as it always shows us all when we allow our mind to be still.