The Vedic Period of India and Pakistan was a civilisation started by the Aryans from the north-west of India, near Kazakhstan. They wrote books, about many things like poems, military, etc., known as the Rigveda, the Samaveda, the Yajurveda, and the Atharvaveda. The Rigveda was the earliest. It includes lots of battles and violence, such as when the king of the Bharatas Kingdom, King Sudas, fought against the Confederation of Ten tribes. The confederation tried to inundate the Bharatas by 'opening the embankments of the Ravi river', yet King Sudas was victorious in the war, with his powerful army. The Bharatas and the Confederation merged into one kingdom, the Kuru, after the war.
In the Early Vedic Period, the Vedics wrote about the "Dasas and Dasyus" who fought with the Vedic Aryans. This could mean the Anartas from the Anarta Kingdom (See map below), though we are not sure.
The tribes could not expand a lot into the Gangetic Plains due to the thick forests, but later, when Iron Tools were invented, they did.
Here is another map of the Vedics, with the boundaries of main kingdoms, or Mahajanapadas, for your reference:
The 'Anarta Kingdom' is a kingdom significantly different, but of the same race, as the Vedics.
Soon, the Shishunaga Empire, from the Mahajanapada of Magadha, rapidly conquered land until it was replaced be the Nandas. The Nandas were very powerful; they managed to (supposedly) scare off the soldiers of Alexander the Great, along with their vassals the Kalingas (Greek: Gandaridae.)
This, however, did not last long, as the Mauryas arrived, and utterly destroyed the Nandas.