Short answers, pulled from the story.
The Chinese Communist Revolution is most commonly dated from the founding of the Chinese Communist Party on the 23rd of July 1921 to the proclamation of the People's Republic of China on the 1st of October 1949. Some historians date it to the later phase of the Chinese Civil War after Japan's surrender in August 1945, while others begin it with the Shanghai Massacre of the 12th of April 1927.
The revolution was led by the Chinese Communist Party, with Mao Zedong emerging as its paramount leader during the Long March in January 1935 after the Zunyi Conference. Other key figures included Zhou Enlai, Chen Duxiu (the party's first General Secretary), and military commanders such as Lin Biao and Zhu De.
The CCP won through a combination of peasant support gained via moderate land reform, effective guerrilla strategy behind Japanese lines during World War Two, and the Kuomintang's collapse under hyperinflation, corruption, and military defections. By the Huaihai Campaign alone, the CCP mobilized 5,430,000 peasants to support its forces, while KMT troops defected in large numbers drawn by the promise of land and better treatment.
The war was decisive in accelerating the CCP's rise. French historian Lucien Bianco argued that economic grievances alone had not been enough to mobilize the peasantry, but the nationalism provoked by Japanese invasion changed that entirely. Over the eight years of war, CCP membership grew from 40,000 to 1,200,000, and historian Chalmers Johnson estimated the party won the support of roughly 100 million peasants in the regions where it operated.
On the 12th of April 1927, Chiang Kai-shek ordered the massacre of Communists in Shanghai, ending the First United Front between the KMT and the CCP. The White Terror spread nationwide, killing tens of thousands of Communists and suspected sympathizers, and the CCP lost approximately two-thirds of its membership. The massacre forced surviving CCP cadres into the countryside, where their experiments with peasant mobilization and land reform laid the foundation for the revolutionary strategy Mao would later systematize.
The Long March was a 9,000 kilometer retreat to northern China that the CCP undertook after the fourth KMT encirclement campaign destroyed their position in south China. During a conference at Zunyi in January 1935, Mao Zedong successfully challenged the party leadership's failed urban strategy and, with Zhou Enlai's support, became chairman of the Politburo and de facto leader of the party. The march cost the CCP roughly 90 percent of its membership but transformed Mao from a regional leader into the undisputed head of the entire organization.