Ok so I’m just gonna correct your title here. Marx believed that after capitalism we will have socialism and then communism. Socialism is producing according to someone’s contribution while communism is contributing to someone’s need (Marx uses different wording but same context). Now as for the Russian revolution, when we say Russian revolution we’re talking about all of the events including the civil war. One of the major players of the revolution and leader of the Bolsheviks Vladimir Lenin was a socialist, and historians and economists even call his form of socialism Leninism and not Marxism. So in short, it was a socialist revolution but not a Marxist revolution.