These questions were answered by Sri. V. Ramanatha Samavedi  M.A., Pradhana Adhyapaka of the Raja Veda Kavya Patasala, Kumbakonam, to the queries posed by the author, with due reverence to the great people whose books were referred.  This FAQ is a humble effort, to appreciate the common queries in minds of millions of youngsters browsing the Net, to rekindle the spirit of belonging to a great heritage and to share the bounty of Vedic Knowledge.  The Author is ready to accept any kind of Corrections / Suggestions.
Q1. What are the Vedas for, are they collection of commentaries on Gods or do they specify ways of living ?
The Vedas are divided into four (The Rig, The Yajur, The Sama, The Atharva) of the 14 Vidyaasthanas (texts that have knowledge and wisdom enshrined in them). These are the doors to Dharma.  Dharma is that which, if we follow, will make us contended and happy.  Thus, these are called Dharma Pramanas, that which gives one true knowledge of Dharma.
Q2. What do the Rig, Yajur, Sama and Atharva Veda contain ?
The whole of the Rig Veda Samhita is in the form of verses, about 10,170 in number (out of 20,500 in all the four Vedas).  'Rik' was the earlier name of 'slokas', a group of Riks are called a 'Sooktha'.  It starts & ends with Agni's praise, symbolizing the light of the soul's consciousness (Atma Chaitnayam) the glow of the soul's awakening.  The first place to Rig, may be because Yajur's actions and Sama's musical recitation emerge from basic Riks.

The word 'Yajus' from 'Yaj' means worship, the word Yajna (sacrificial worship) also derived from it.  It gives a practical shape to in the form of Yajna.  It describes in prose the procedural details of different Yajnas.  The main branches are Sukhla (white) known to be learnt from the Sun God, Surya, and the Krishna Yajur Veda (black).  The glory of Yajur Veda lies in its good presentation of vedic karma or rituals.  Yajnas like Darsa Poornamasa, Somayaga, Vaajapeya (are you thinking of Vajpayee! actually it means one who has conducted this Yajna), Rajasooya, Aswamedha and many other in all their procedural detail by the Thaitreeya Samhita in Krishna Yajur Veda.

Yajur is of special significance to Advaitins -  those who understand and believe in the "non-dualism" school of philosophy, that declares that there is but One Reality, that the individual self and the Brahman are one.  (Jeevatman and the Paramatman reside in you as same).  Any philosophical doctrine should contain a  Sootra or Aphorism, to enunciate the doctrine in a condensed and pithy form.  Bhaashya is detailed commentary and Vaartika, a further elaborate elucidation of the Bhaashya.

Atharva means purohit, named after Rishi Atharvan, who brought it to light.  The Athava Veda contains many types of mantras to ward off evil, hardship and to destroy enemies.  Also, many hymns dealing with creation esp.  "Prithivi Sooktham", the hymn extolling the wonder of creation.  The Upanishads are Prasna, Mundaka and Madukya, where the third one helps in ensuring Moksha or liberation of soul from continuous births.
Q3. What are the classifications & sub-classifications in Vedas?  What do the others signify ?
To understand the classifications one should know the Vidyaasthanas : the four Vedas, the Six Vedaangas or auxiliaries to the Vedas viz.   

                  a.  Siksha which is euphony and pronunciation;
                  b.  Vyaakarna which is grammar;
                  c.  Chandas which is meter;
                  d.  Niruktha or etymology;
                  e.  Jyotisha or astronomy;
                  f.   Kalpa or procedure;
                  g.  Meemaamsa or interpretation of Vedic Texts;
                  h.  Nyaaya or logic;
                  i.   Puraana or mythology and
                  j.   Dharma Saastras which contain the codes of conduct.

The four Vedas from the core of the Vedic religion.  They are the supreme authority - Pramaana.  The Vedas form the basic structure from which have been derived the 6 Vedangaas and the 4 Upaangaas, in order to supplement the understanding of the Vedas.  The Vedas are meant to be studied with the other ten of its constituents.

The following table gives the various branches of the 4 Vedas.
Vedas
Veda Sakha
Samhita / Brahmana
Aranyaka
Upanisad
Rig
Sakala
Aitreya
Aitreya
Aitreyopanisad
Sankhyana
Kausitaki
Kausitaki
Kausitaki
Yajur
Tairiya



Sama
Ranayaniya
Jaiminiya
Kauthama
Pancavimsa, Arseya, Vamsa, Talavakara
Diavata, Jainminiya Upanishad, Sadvimsa, Mantra, Chandogya
Samavudhana
Samhitopanishad

Kenopanisad
Chandogyopanisad
Atharva
Saunaka
Pippalada
Gopatha

Mundako, Mandukyo
Prasnopanisad
The 'Samhita', which means that has been collected and arranged, is the main text portion, the hymns, while the 'Braahmanas' lists the Vedic Karmas (rituals to be performed).  When the mantras contained in a Veda Samhita are converted into action, called Yajna, the Braahmanas serve as a guidebook or handy manual explaining how each word should be understood, or what construction should be placed on each word used i.e. the proper use of the mantra.

'Aranyaka' is derived from the 'Aranya' (forest).  The chanting of Vedas, the Yajnas and other rituals are for materialistic benefits, for those living in homes, but only preliminary.  It has to be understood that these rituals are intended to confer mental purity ( Chiththa Shuddhi ) by constant discipline.  For this, one must seek solitude of forests for meditation on the true nature of the self and true nature of reality.
Raja Veda Kavya Patasala. All rights reserved - 2013