Pongal

Disclaimer - This is taken from Various sources

The first day is known as 'Bhogi Pongal,' which is used to clean and decorate the house. The second day is called 'Thai Pongal,' and it is when new rice is gathered and cooked. This is the time when the Sun God is honoured. This day coincides with Makar Sankranti, India's winter harvest festival, which marks the beginning of the sun's six-month trip north and warm.

The third day is known as 'Maatu Pongal,' and it is entirely dedicated to the cattle symbolised by a cow. On this day, it is usual to clean and adore the cows. The fourth day is known as 'Kaanum Pongal,' which is a day for family get-togethers. Birds are revered on this day. Cooked rice balls are produced and placed outside for birds to consume. People also express gratitude to their relatives and friends.

Devotees offer all the dishes in 9 leaves. But in general, they spread 5 leaves for the Sun God. In those 5 leaves, they keep sweet Pongal, Vella Pongal, Pongal sambar, kootu in little quantities. Just in the middle of the rangoli- kolam, a huge and mammoth figurine of the Lord Surya (Sun God) with the glittered beams are also chiseled.

Light two lamps in front of the banana leaves. Spread a banana leaf and keep all the seasonal vegetables like sweet potato, pumpkin, yam, arbi, Panag kizhangu. Keep sugar cane pieces, banana, betel leaves & nuts. Break a coconut and keep it. Now do the puja and mangala harathi. Finish the puja. After the puja, a glass of milk sweetened with jaggery is distributed which is known as “siruveetu paal”.

Reference - 

https://rgyan.com/en/festival-detail/pongal-rituals-and-puja-vidhi