I hope my English makes some sense, I'm a bit insecure about it.

The Nuremberg Laws of 1935 were announced to the German Reichstag at the annual Nuremberg rally of NSDAP. The foremost purpose of these laws was to seclude Jews and other non-Aryans from the "pure blooded" German population. The laws basically stripped the Jewish population of their civil rights and citizenship and made them literally "second class citizens".

The first law, "The Law for the Protection of German Blood and German Honour", forbade marriages between Germans and Jews. It also forbade extramarital relationships. Breaking this law was known as "Rassenschande" - racial desecration. It was considered a serious crime and could lead to imprisonment. "Jews" were not allowed to employ "German" females under the age of 45 in their households. Display of German flag and/or national colours was also forbidden from "non-Aryans".

The second law, which was called "The Reich Citizenship Law" declared that only those who were considered Aryan were German citizens. Others were declared to be "State subjects". Basically civil rights were denied of anyone who wasn't pure blooded Aryan. This meant that they couldn't for example vote or hold an office. This being done it was easy to decree new antisemitic/otherwise discriminating laws later.

A precise definition to a citizen's "Jewishness" and "non-Jewishness" was declared. Anyone who had four German grandparents, was of "pure German blood". If a grandparent had belonged to a Jewish congregation, they were considered Jewish and so their grandchild was called "Mischling", a "cross-breed". This meant that also a person who had never practiced Jewish religion, or in extreme cases hadn't even been aware of having Jewish grandparents, could be declared to be at least part "Jewish" and thus denied their civil rights.