Complex sentence: Zia returned to Pakistan the following year and was promoted to Major and transferred in October 1970 to be second-in-command of the 8th East Bengal regiment stationed in Chittagong.
Split into simpler sentences: Zia returned to Pakistan the following year and was promoted to Major. He transferred in October 1970 to be second-in-command of the 8th East Bengal regiment stationed in Chittagong.