You have become little familiar with Vedic literature in class 11. You have also become little acquainled with Vedanga literature along with Vedic Samhita. With that in mind let us cultivate more familiarity with Vedic literature.
There is concept of a person named 'Ved' in Vedic literature and (as a man has limbs like mouth, nose, eyes, ears, hands and legs to protect himself) to protect this man 'Ved' six limbs (means Vedangas) like (as a nose) education, (as a hand) Kalp (as a mouth) grammar, (as ears) Nirukta (as legs) Verse and (as eyes) astrology are a written/constructed.
Out of those Vedangas we will be familiar with the Kalpa Vedanga. It is said while introducing Kalpshastra that कल्पो वेदविहितानां कर्मणाम् आनुपूर्वेण कल्पनाशात्रम् । i.e. Kalpanashastra wherein acts/actions to be done or performed said in the Veda are imagined in a definite order, is 'Kalp'. The idea is that to think of a plan to perform the deeds / action said in the Veda in a definite order is the subject of Kalpshastra. There are four parts of it -1. Srotrasutra. 2. Gruhyasutra. 3. Dharmasutra and 4. Shulvasutra.
Out of all these sutras Gruhyasutra literature is very important for many reasons like (1) It is related to family life. The 'Gruhastha Jivan kala' of a person is linked with his ancestors and his progeny in the form of children. So in one way, this period of life is the best period linked with not only one but three generations. It is very natural that works / deeds to be performed during this period are related to all these three generations.
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The subject of this Gruhyasutra is also the 'Vidhi- Vidhan' of sixteen Sanskaras that have become popular for refinement of human soul. (3) The iniformity that we find in the performance like marriage, Upanayan ie. through ceremony and burials is also due to Gruhyasutra.
Literature of Gruhyasutra as the part of Vedic Literature (Kalpshastra) is very much detailed. Today ninetten Gruhyasutras three of Rugveda, one plus nine of Yajurveda, five of Samveda and one of Atharvaveda are available out of all these nineteen sutras 'Aslayan' and 'Paraskar' Gruhyasutra and the most popular. Aslayan Gruhyasutra is belieived to be the oldest. The writer, the composer of this Aslayan Gruhyasutra is Acharya Aslayan. In this Gruhyasutra the method of Sanskras is presented in a very simple way. The composer of Paraskar Gruhyasutyra is Acharya Paraskar. It is belieived to have been written in second century B.C. There are three chapters in it. Every chapter is internally devided into 'Kandikas' (cluses) Considering all the three chapters there are totally fifty one 'Kandikas'.