If the limbs and sub-limbs of yama and niyama are to be practiced, steps should be taken to ensure that one does not fall victim to disease, obligation or poverty.
For when a person becomes ill, his mind cannot be steady, nor can he do any work. Therefore, the body, sense organs and mind must be stabilized to prevent obstacles, such as disease from occurring.

To bring the body and sense organs under control, the asanas (postures) should first be studied and practiced. Asana is the first step in the practice of the limbs of yoga.

It is not possible to practice the limbs and sub-limbs of yama and niyama when the body and sense organs are weak and haunted by obstacles. To destroy diseases of the body and sense organs, asana must be studied and practiced, which is why Swatmarama speaks of it as the limb to be undertaken first. From its practice, the body will be conditioned and this, in turn, will lead to improved health.

It is said that asana is primary, due to its being the first limb of hatha yoga. One should practice that asana which is a state of steadiness, freedom from sickness and lightness of body.

Hatha:
ha = the surya nadi
tha = the chandra nadi

The process of controlling the breath that moves through these two nadis is known as hatha yoga. Yoga means relation and strength. If the air we breathe throught the nostrils is governed by the rules and practice of pranayama, or breath control, the mind will be arrested:
the breath being in motion, the mind is moving. The breath being without motion, the mind must be motionless.

If our breath is moving and unregulated, the mind will be unsteady. Regulating the breathing stabilizes the mind and makes it firm. The methof for directing the stabilized mind toward the Inner Self is what is known as hatha yoga.

Niyama:
Shaucha
Santosha
Tapas
Swadhyaya
Ishwarapranidhana

Shaucha:
two types of shaucha (purification): bahir shaucha (external purification) and antah shaucha (internal purification)

Bahir shaucha: washing the outer part of the body
Antah shaucha: viewing everything and every being as a friend, and treating all with affection (maitri)

Santosha: contentment (a state of happiness and satisfaction)
Keeping the mind focused in a single direction, always being happy and never feeling regret for any reason, this is santosha.

Tapas: observances performed to discipline the body and sense organs.
The perfection of the body and sense organs is due to intensity in spiritual practice, being the eliminatioin of imurities.

Swadhyaya: the recital of Vedic verses and prayers in accordance with strict rules of recitation.
The Gayatri mantra forms the basis for the study of all Vedic verses or mantras
The Gayatri is a verse of the sacred Rg Veda addressed to the Sun, and is held to be the holiest passage.

Ishwarapranidhana: surrender to God. Carrying out all our actions, spoken or unspoken, without desiring their fruit and offering their fruit to the Lord.

Whatever I do, whether out of desire or not, good or bad, having surrendered all that to you, I act as directed by you.

Through ishwarapranidhana, samadhi (union with the Supreme) is attained, which in turn leads to the attainment of perfectio and fulfillment.

Yama, the first limb consists of five parts:
Ahimsa
Satya
Asteya
Brahmacharya
Aparigraha

Only the actions of previous lives will lead us to practice them. The mind will turn itself to the practice of yoga only when a samskara or vasana is present. (it is believed that only an association with the practice of yoga in a past life will lead to its practice in the present life

Ahimsa: not causing injury to anyone, including animals - in any form, at any time, or for any reason. In word, thought or deed.

Satya: truthfulness.
One should always tell the truth in thought, word and deed. The truth must be pleasant to others and an unpleasant truth should not be uttered. If one follows the truth in this manner, all one's words will become true and all one's desires will be fulfilled.

Asteya: not stealing the property or possessions of others. Being envious of or begruding another. Cheating someone with sweet words. Gaining selfish ends under the guise of truthfulness: all are to be abandoned.

Brahmacharya:
Upon being established in brahmacharya, there is the attainment of vital energy.
Brahmacharya is very difficult nowadays because there are so many things that attract the mind in different directions: theaters, tv, restaurants, internet. But you still can achieve some degree of Brahmacharya. If he is to achieve it, he must avoid:
mixing with vulgar people
going to crowded areas for recreation
reading vulgar books which disturb the mind
going to theaters and restaurants
secretly conversing with strangers of the opposite sex.

Upon being established in brahmacharya, vital energy is obtained.

Moksha or mukti: spiritual liberation

Householders lose brahmacharya owing to seminal loss. With the loss, they lose the strength of their bodies, minds and sense organs. In addition, moksha and the capacity to perceive the soul or realize the true Self become impossible. In the absence of the knowledge of one's own Self, one remains in the cycle of birth and death, and thus must continue to suffer in this sapless and despicable world.

Nose nostrils:
right one: surya nadi
left one: chandra nadi

Dharma: righteousness
Artha: wealth
Kama: desire

Nayam atma balahinena labyah The Self cannot be gained by the weak

Aparigraha: the food we eat should be pure (sattvic), untainted (nirmala) and acquired through righteousness. Not be secured by cheating, deceit, persecution or other unjust means.
Only taking as much food as we need to maintain our bodies and not desiring things of enjoyment which are sueprfluous to the physical body, is aparigraha.
If the limb of aparigraha is firmly practiced, details of previous and future births are revealed.