In which of the 4 Vedas procedures of ritualistic worship are mentioned?

Question

Details of worship procedures are laid down in which Veda? Like details of how to do a Puja or Homa?

Answer 1

Interesting question, as most the ritualistic worship today of Vedanta is founded in the Tantras and most from the Brahmana portions of the Vedas. On this subject Swami Vivekananda said (Complete Works, V4, pp335-336, available here under Writings: Prose subheading Reply to the Madras Address - http://cwsv.belurmath.org/volume_4/vol_4_frame.htm):

The three Prasthânas, ("Courses", viz, the Upanishad (Shruti), the Gita, and the Shariraka-Sutras.) then, in their different explanations as Dvaita, Vishishtadvaita, or Advaita, with a few minor recensions, form the "authorities" of the Hindu religion. The Purânas, the modern representations of the ancient Nârâsamsi (anecdote portion of the Vedas), supply the mythology, and the Tantras, the modern representations of the Brâhmanas (ritual and explanatory portion of the Vedas), supply the ritual. Thus the three Prasthanas, as authorities, are common to all the sects; but as to the Puranas and Tantras, each sect has its own.

The Tantras, as we have said, represent the Vedic rituals in a modified form; and before any one jumps into the most absurd conclusions about them, I will advise him to read the Tantras in conjunction with the Brahmanas, especially the Adhvaryu portion. And most of the Mantras, used in the Tantras, will be found taken verbatim from their Brahmanas. As to their influence, apart from the Shrauta and Smârta rituals, all the forms of the rituals in vogue from the Himalayas to the Comorin have been taken from the Tantras, and they direct the worship of the Shâkta, or Shaiva, or Vaishnava, and all the others alike.

Indeed, Arthur Avalon (Sir John Woodroffe) in his work Shakti and Shakta: Essays and Addresses on on the Shakta tantrashastra says (Chapter 26: Shakta Sadhana (The Ordinary Ritual):

We are perhaps, therefore, correct in saying that it comes to this: In a bad age, such as the Kali, men are (to say the least) very scarce, though common-sense and experience must, I suppose, allow for exceptions. Whilst the Pashu natural disposition exists, the Vaidik [vedic] ritual which he should follow cannot be done. It is in fact largely obsolete. The Vaidik Pashu or man who followed the Vaidik rituals in their entirety is non-existent. He must follow the Agamic rituals which, as a fact, the bulk of men do. The Agama must now govern the Pashu, Vira, and would-be Divya alike.

As I have frequently explained, there are various communities of the followers of Tantra and Agama according to the several divisions of the worshippers of the five Devatas (Pancopasaka). Of the five classes, the most important are Vasihnava, Shaiva and Shakta. I do not, however, hesitate to repeat a statement of a fact of which those who speak of 'The Tantra" ignore.

The main elements of Sadhana are common to all such communities following the Agamas; such as Puja (inner and outer), Pratima or other emblems (Linga, Shalagrama), Upacara, Sandhya, Yajna, Vrata, Tapas, Mandala, Yantra, Mantra, Japa, Purashcarana, Nyasa, Bhutasuddhi, Mudra, Dhyana, Samskara and so forth. Even the Vamacara ritual which some wrongly think to be peculiar to the Shaktas, or was followed (I am told) by other Sampradayas including Jainas and Bauddhas. Both, in so far as they follow this ritual, are reckoned amongst Kaulas though, as being non-Vaidik, of a lower class.

A main point to be here remembered, and one which establishes both historical and practical importance of the Agamas is this: That whilst some Vaidik rites still exist, the bulk of the ritual of to-day is Agamic, that is, what is popularly called Tantrik. The Puranas are replete with Tantrik rituals.

...

The materials used or things done in a Puja are called Upacara. The common number of these is sixteen, but there are more or less (see Principles of Tantra, Part ii). The sixteen which include some of the lesser number and are included in a greater are: (1) Asana (seating of the image), (2) Svagata (welcoming of the Devata), (3) Padya (water for washing the feet), (4) Arghya (offerings which may be general or Samanya and special or Vishesha) made in a vessel, (5), (6) Acamana (water for sipping and cleansing the lips -- offered twice), (7) Madhuparka (honey, ghee, milk and curd), (8) Snana (water for bathing), (9) Vasana (cloth for garment), (10) Abharana (jewels), (11) Gandha (Perfume), (12) Pushpa (flowers), (13) Dhupa (incense), (14) Dipa (lights), (15) Naivedya (food), and (16) Vandana or Namaskriya (prayer).

You may want to read Arthur Avalon's book in its entirety before consulting other books as it will give you many references and a good background.