Complex sentence: On 12 April, Chiang Kai-shek started his counter-revolutionary war in Shanghai, and Xiang Jingyu decided to flee to Wuhan and work in the Propaganda Department of the Federation of Trade Unions of Wuhan.
Split into simpler sentences: On 12 April, Chiang Kai-shek started his counter-revolutionary war in Shanghai. So Xiang Jingyu went to Wuhan and worked in the Propaganda Department of the Federation of Trade Unions of Wuhan.