How did the maurya empire begin?

Answer 1

By expelling the Greeks

Answer 2

At its greatest extent, it stretched to the north to the natural boundaries of the Himalayas and to the east into what is now Assam. To the west, it reached beyond modern Pakistan, annexing Balochistan and much of what is now Afghanistan, including the modern Herat and Kandahar provinces. The empire was expanded into India's central and southern regions by the emperors Chandragupta and Bindusara, but it excluded extensive unexplored tribal and forested regions near Kalinga which were subsequently taken by Ashoka.

Answer 3

it started or began in the Himalayas and went on from there