Complex sentence: Zhang with Li Lisan and Qu Qiubai were the acting leader of CPC at that time when Mao only led a small troop with riot in Jiangxi and Hunan.
Split into simpler sentences: Zhang with Li Lisan and Qu Qiubai were the acting leaders of CCP. At that time Mao only led a small number of troops in Jiangxi and Hunan.