Complex sentence: Headquartered in Changsha (in what is now Hunan province), he patiently built up his forces; only in late 1658 did well-fed and well-supplied Qing troops mount a multipronged campaign to take Guizhou and Yunnan.
Split into simpler sentences: Headquartered in Changsha (in what is now Hunan province), he patiently built up his forces. Only in late 1658 did Qing armies mount a multipronged campaign to take Guizhou and Yunnan.