The link you posted was good, too. One thing I would observe though,
There’s one last lesson to remember. The inhuman atrocities committed by the Nazis occurred relatively late on their timeline. By the time the Nazis were resorting to torture, mass murder and military aggression, they’d been established for at least a decade. If rampant brutality is your only gauge for recognizing a dangerous regime, you’ve missed a few red flags along the way. And worse, you’ve waited too long to stop it.
While the systematic extermination of the Jews didn't start until 1940, the first concentration camp (for political prisoners, etc.) opened just a few weeks after the Enabling Act handed Hitler effectively unlimited power.