Complex sentence: The Chagharzais occupy the country on either side of the river Indus, those cis-Indus being located on the western slopes of Tor Ghar (Black Mountain), to the north of the Akazais.
Split into simpler sentences: The Chagharzais occupy the country on either side of the Indus river. They are located on the western slopes of Tor Ghar (Black Mountain), to the north of the Akazais.