Short answers, pulled from the story.
Adolf Hitler became chancellor of Germany on the 30th of January 1933 after striking a backroom deal with Franz von Papen. The Nazis had no plan for concentration camps prior to their seizure of power, but the system arose in the following months due to the desire to suppress tens of thousands of Nazi opponents.
Theodor Eicke was appointed the first inspector of the Concentration Camps Inspectorate in December 1934. Only camps managed by the IKL were designated concentration camps under his leadership which began standardizing the system.
Auschwitz became the deadliest concentration camp and the center of the camp system during the second half of the war. It swelled in size fueled by the deportation of hundreds of thousands of Jews and held 74,000 of the 224,000 registered prisoners in all SS concentration camps by August 1943.
By the end of the war only 5 to 10 per cent of the camp population was Reich Germans from Germany or Austria. Most prisoners were people from countries occupied by the Wehrmacht including Eastern Europeans who predominated in some camps during the first half of the war.
Major evacuations occurred in mid-1944 from the Baltics and eastern Poland January 1945 from western Poland and Silesia and March 1945 from concentration camps in Germany. Both Jewish and non-Jewish prisoners died in large numbers as a consequence of death marches deliberately ordered by Himmler to keep prisoners under Nazi control.