How was genghis khan able to unite the nomadic mongols

Genghis Khan has a friend called Jamukha, Jamukha was an heir of the Jadaran tribe. Together they mannish to retake the power over his tribe that was stolen from him when his father were killed, he also mannish to retake an Mongolian Union that his father form. His power grow bigger and stronger as he attack his enemy and uniting the tribe in the Mongolian Union