In WWI he was just a footsoldier. Used to run about the trenches giving out messages.
When WWII came round he wanted more trenches because he loved it! And he did an amazing job at re-arming Germany, but he did have help. I don't know if you've heard of a German company called Krupp Works, but they supplied Hitler with all his weapons from the 1930s until the end of the war.
Krupp Works, and Faber were two of the biggest businesses in Germany, and they poured millions of Marks into the Nazi party. As did other companies. Henry Ford did too!
But, yeah, Hitler headed the whole thing. He did have his people doing all the dirty work, but he headed the whole 'operation' - he told everyone what to do, and the people below him interpretted the orders and carried them out in their own ways.