The procedure described below is what is generally followed in the Veda pathasalas.
Vedadhyayana involves first of all learning the texts by heart (kanthastheekaranam).
1. Aksharabhyasa - learning of the grantha script.
2. In the first stage, the sub texts are learned by heart. They are -
Taittiriya brahmanam - elaborating the procedure of yajnas etc.
Aranyakam, Kathakam and Upanishad - the spiritual texts mostly dealing in adhyatma.
This stage takes about two and a half years.
3. In the next stage which make take about two years, the brahmachari learns by heart the taittiriya samhita comprising of 2198 panchasatis ( blocks of 50 words each). They are the mantras in prose form.
4. In the next stage called pada patha the entire samhita is split word by word and learned.
5. In the next stage called krama patha, the brahmachari learns to combine the words and how svara and pada sandhis are formed. The first word of the mantra is joined to the second, second to the third etc.
1+2, 2+3, 3+4, 4+5.
6. The next stage is called jata patha the sequence is
7.The final stage is ghana patha in which the sequence is
On completion of this stage the student receives the title called ghanapati which is highly respected.
Then the student moves onto learn the nuances of pronunciation and svaras through lakshnas and becomes a salakshana ghanapati. It can take upto ten years to reach this stage.
8. Further to this one can move onto specialise in
Shadangas - the six organs of the vedas
Bhashyam - meaning and commentary
Pryogas - srautha and gruhya prayogas.
To become a karmakandi purohit who does the regular household paurohitya all the above are not required. Proficiency in the relevant mantras ( may be about 1% of the whole) and a few months of training under an able acharya are sufficient.
In the video below Mrityunjaya mantra is chanted in Samhita - Pada - Krama - Jata - Ghana formats.