This festival is the biggest festival of India. Diwali indicate the spiritual "victory of Light over Darkness and Good over Evil". On this day Lord Ram, Laxman and Maa Sita came back to Ayodhya.
This festival is started with small festivals like:
Dussehra - It is a Hindu festival celebrated every year at the end of Navratri. It also known as Vijayadashmi because on this day Ravan Dahan was done.
Karva chauth - Karva chauth is a festival celebrated by Hindu women, on this day they keep fast for the whole day for their husbands long life and break their fast at night after seeing the full moon.
Dhanteras - It is the first day which indicates the festival of Diwali. It is celebrated on Krishna Paksha as on this day Lord Dhanvantari was born. There is a traditional trend to buy something new specially brass, silver and gold. On this day we worship Lord Dhanvantari and Maa Lakshmi.
Narak Chaturdashi - It is also called Chhoti Diwali. It is celebrated because on this day an asur (demon) Narakasur was killed by Lord Krishna, Satyabhama and Maa kali.
What we do on Diwali?
On Diwali we decorate our houses by making rangolis and by hanging up lights on their walls and light up deepak everywhere in our homes, temples, shops etc. we light fireworks and ate sweets. We worship Lord Ganesha and Maa Lakshmi on this day.