I'm usually up for answering these types of questions, but I'm tired tonight, so I'll just touch on a few basics and I'll probably come back later with some pretty good sources to help you out.
Communism in the Soviet Union began as an attempt to create the first dictatorship of the proletariat, using Marxism and the Paris Commune of 1871 as the guide. The proletariat is the industrial working class. To really get a sense of Russian communism, one must analyze Trotskyism, which is Leninism, and Stalinism. Leninism-Trotskyism is internationally based. It works on the principles of an elected body that serves as both legislative body and executive body. However, Stalinism, works on the principle of "socialism in one country," which was actually a slogan used by Stalin to consolidate power around his image of what Russia should be, while rejecting the democratic principles found in Leninism-Trotskyism.
In China, Mao Tse-tung took Stalinist principles, with the help of Russian advisers and created a peasant revolution, which really doesn't make sense if you take the time to read Marx or Lenin. The peasant class is usually unprepared for revolution and is often very backward, which I was really helpful for Mao, who largely failed to grasp any notion of Marxism, just as Stalin failed to do the same.
Hope this helps, like I said, I'll touch it up later.
