Kundalini raising and uniting it with Sahasrara Chakra is one of the very easiest way to get Mokshya. It mostly exists in hidden form in our texts, it is because Gods (devatas) do not want us that we achieve salvation easily as cited in Brihadaranyaka Upanishad(1.4.10) also cited in the starting of Shiva Gita in Padma Purana.
Although it is in hidden form in all our texts. But still we can get direct information about it by the grace of great Acharyas like Adi Shankara, Guru Gorakhnath, Mahavatar Babaji, Ramakrishna Paramhamsa, Swami Vivekananda and others.
Adi Shankaracharya also told uniting Kundalini Shakti from Muladhara to Sahasrara chakra is same as being uniting with Brahman. Here is an excerpt from Traditional Shankara Digvijaya:
Shankara Digvijaya Canto 12
(25-37) Then the Acharya reached the temple of Mookambika of great spiritual power, which was surrounded by a dense and attractive growth of trees and plants like mango trees, jack trees, palms, pomegranates, sugar cane and the like. With eyes brimming with tears of bliss and with all the hairs on end, that great sage
Sankara, possessed of the spirit of universal benevolence, recited the following hymn in praise of the Divine Mother with a heart
overflowing with devotion: "0 Mother! It is the three hundred and sixty rays of light proceeding from Thy lotus feet that reflect
all through the year as the light of the sun, the moon and the fire. Men versed in Thy worship according to the ritualistic code adore Thee with sixtyfour proceedures of worship and with rich offerings including costly garments. Others worship Thee with non-material offerings. They offer Thee worship with these sixtyfour procedures
in the six psychic centres along the Sushumna path. Ordinary people worship Thee with material offerings; middling devotees with mental offerings followed by physical offerings; and great ones with spiritual worship only. But when one is established in Non-dual Consciousness, no question of worship or adoration
arises. Thou hast thirty eight aspects, of which five lead to liberation. Wise men always adore Thy feet which excel every other aspect. As the fire of cosmic destruction, Thou bumest up the
universe; as life-giving ambrosia, Thou createst the worlds; and as the soul of immortality, Thou preservest it and redeemest the Jivas. Those who contemplate Thee in these three aspects attain spiritual felicity. Those who want to adore Thee first grasp the truth about Thee from the instruction of the Guru, then realise it in Samadhi, and attain to the state of Non-duality. Those who meditate on Thee in the lowest Chakras, known as Muladhara and Swadhisthana, are prompted by worldly desires and attain only to them. Those who adore Thee in Manipura just reach the gate of Thy spiritual being. Those who meditate on Thee in the Anahata-chakra, attain to Thy region; those who do so in the Visuddhi-chakra attain closeness to Thee; and those doing 'so in the Ajna-chakra attain to equality of bliss with Thee. The highest type of Sadhakas who meditate on Thee in the thousand-petalled lotus in the head, known otherwise as Dhruva-mandala, overcome the interest in the four forms of communion and attain to oneness with Thee. These four forms of communion are: the unity of Sri Chakra and the six Chakras in the body; the unity of the Mantras pertaining to the Sri Chakra and the· six Chakras; the unity of Sri Chakra and Thyself; and the unity of the Mantras of Sri Chakra and Thyself. The Sadhaka recognises all these forms of unity."
Thus as Adi Shankara tells "attain to oneness with Thee"... Thus denoting we become Brahman by that.
Guru Gorakhnath in his Hatha Yoga Pradipika states that those who have awakened kundalini obtains ParamPadam (Highest state)
Suptā ghuruprasādena yadā jāgharti kundalī
Tadā sarvāni padmāni bhidyante ghranthayoapi cha ।।2।।
When the sleeping Kundalinî awakens by favour of a guru, then all the lotuses (in the six chakras or centres) and all the knots are pierced through.
Prānasya śūnyapadavī tadā rājapathāyate
Tadā chittam nirālambam tadā kālasya vañchanam ।।3।।
Susumnâ (Sûnya Padavî) becomes a main road for the passage of Prâna, and the mind then becomes free from all connections (with its objects of enjoyments) and
Death is then evaded.
Śaktimadhye manah krtvā śaktim mānasamadhyaghām
Manasā mana ālokya dhārayetparamam padam ।।54।।
Placing the mind into the Kundalini, and getting the latter into the mind, by looking upon the Buddhi (intellect) with mind (reflexively), the Param Pada (Brahma) should be obtained.
Thus one gets united with Brahman when Kundalini is awakened and gets united to Sahasrara chakra.
Great Yogi Rama Krishna Paramhamsa also told the same:
Gospel of Ramakrishna
Awake, Mother! Awake! How long Thou hast been asleep In the lotus of the Muladhara! Fulfil Thy secret function, Mother: Rise to the thousand-petalled lotus within the head, Where mighty Shiva has His dwelling; Swiftly pierce the six lotuses And take away my grief, O Essence of Consciousness! [Page no. 267]
Swami Vivekananda in commentary of 1.34th Patanjali Yoga Sutra says:
One they call Ida, another Pingala, and the third Susumna. Pingala, according to them, is on the right side of the spinal column, and the Ida is on the left side, and in the middle of this spinal column is the Susumna, a vacant channel. Ida and Pingala, according
to them, are the currents working in every man, and through these currents, we are performing all the functions of life. Susumna is present in all, as a possibility; but it works only in the Yogi.
In the commentary of 2.50th Sutra he says:
By place is meant that the Prana is held to
some particular part of the body. By time is meant how long the Prana should be confined to a certain place, and so we are told how many seconds to keep on motion, and how many seconds to keep another. The result of this Pranayama is Udghata, awakening the Kundalini.
Thus one gets united with Brahman when Kundalini pierces the Sahasrara chakra. It is same as being one with Brahman. If you take it as being same with Shiva residing in Sahasrara with Saguna aspect then it is equivalent to Sayujya mukti. If you have theory of duality ie, Jiva can never be Brahman then such type of Mokshya is equivalent to Ekatwa ie. just united with Atman not Brahman.. Thus it depends on your belief about the type of Mokshya yogi get from this type. If Non Dualism is right then person is united with Brahman and hence mokshya is eternal and if Dualism is right person is united with his Atman only [ie.Ekatwa] thus is non-eternal.
For the location of 7 chakras in our body one doesn't require hidden meaning of scriptures also. One can get direct knowledge by Pratakshya Praman (ie. Direct Perception)..
The place where solid waste comes is associated with solidity (ie.Bhu tatwa) thus named as Muladhar.
The place where liquid waste (Jala tatwa) comes in our body is located just above it. Thus that area named as Swadhisthana .
Above it is the place where Agni tatwa causes digestion in our body thus Manipura is named in that area.
Above it is the place where Vayu tatwa is in our body.( ie. Lungs is there). Thus that area is named as Anhata.
Above three chakras are related to Akash tatwa each goes on being more subtler on going above. First sound produced from vocal chord which is element of Akash tatwa, that area named as Vissuddha. Then light perceived in the eye area named as Ajna. And the most subtlest which even transcends Akash Tatwa is pure consciousness thus that area named as Sahasrara chakra.
Thus these 7 chakras are the representation of elements from below ie Bhu tatwa, Jala tatwa, Agni tatwa, Vayu tatwa and Akash tatwa and thus finally transcending the Akash tatwa too. Thus Mokshya happens when Kundalini shakti goes on transcending these Panchamahabhuta. Thus the location and function of each chakra can be directly perceived by direct perception....