Hitler wanted to create a strong and dominant Germany. He wanted to destroy the Versailles Treaty while uniting all German speakers and creating Lebensraum in the east. He used a combination of long-term goals and opportunism to gradually revise the treaty throughout the 1930s.
He rearmed Germany, contrary to the Versailles Treaty and occupied the Rhineland and Austria – both were forbidden by Versailles. The Sudeten crisis of 1938 led to the very real threat of a wider European war.
This ultimately led to the occupation of Czechoslovakia and eventually Poland in 1939. The attack on Poland was to be the trigger that led to Britain and France declaring war on Germany.