All are totalitarian dictatorships. Communism is a stage of Marxism described by Karl Marx, where one dictator is supposed to ensure perfect socialism. It is socialist in nature.
In practice, it has almost always turned into an unfair, totalitarian dictatorship that doesn't care about the people. The idea was made by Karl Marx and Lenin first put it into practice in Russia. Stalin then took over after Lenin died, and Stalin's communism is what we usually think of when we think of Communism today.
Nazism is "National Socialism". It derives influence from both fascism and Marxism(Karl Marx's socialism), and has aspects of both. Meaning it focuses on a strong central government, nationalism, and socialism.
However, Nazis hate Communists. Nazism was made by Hitler in Germany. Fascism is another form of totalitarian dictatorship that focuses on nationalism (pride in one's own nation) and a strong central government.
Fascism was made by Mussolini in Italy. All forms of government used fear to oppress the people. Hitler and Mussolini used secret police, as well as "stormtroopers"(Hitler) and "brownshirts"(Mussolini) to punish, imprison, or kill people who opposed them.
Stalin also killed millions of Russian civilians who he believed were plotting against him (in reality Stalin was paranoid). All forms of government relied very heavily on propaganda.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.