The Nazi party got its start in 1920, but the beginnings of its ideologies date back much further. From as early as 1834, the phrase 'national socialism' has been put in print and used throughout Europe. In 1898, Stein in Eger organized the German Workers Congress, which would become the German Workers' Party and then the National Socialist German Workers Party (Nazi Party) by 1920. They staged many uprisings and attempted coups during the early 1920s, and once Adolf Hitler became their leader, the goal was to overtake the government and create a new government based on their ideals in Germany.
This was first done by way of a coup, but failed and ended up with Hitler serving 9 months in prison. Upon his release, he chose to take the legal, official route to public office. The Nazis believed in a "Master Race" and their fascist ideals are what set the stage for the future that they were about to create. The goal, in Nazism, was to eliminate anyone who was 'inferior' by way of race, religion, gender, sexuality, political belief, mental disability, illness, or age. They believed that the Third Reich (their name for the totalitarian state they wanted to create) was the only way to govern a country and accomplish their goals.
Nazism found its roots in fascism, anti-Semitism, and anti-communism. Their goal was to dominate society and purge those who were inferior to keep their society strong and powerful as a force in the global world, which they had believed to have become too diverse and filled with 'inferiors'. By 1934, Hitler had gone from being the leader of the Nazi Party to the dictator and chancellor of Germany, which put the Nazis in the perfect position to carry out their plans to cleanse their society of anyone 'less than'.
Their belief that the Aryan race was the 'Master Race' is what fueled their actions. They started their plight with laws and discrimination against Jews and other inferiors, but by the time Hitler was removed from power the Nazis had essentially become mass murderers, killing millions of Jews and other people who didn't meet their standard for the master race that they had in mind. Although the large Nazi movement disbanded after Hitler's death in 1945, there are still followers of this ideology today. They are in much smaller groups and spread throughout the world, but Nazism goes well beyond Germany and World War II.