What does the supreme court do

Our country was the first to have a Constitution that separated power into three parts: those who make, enforce, and interpret the law. In general the legislative branch (Congress and each state legislature) makes the law, the executive branch (President and Governors of each state) enforces the law, and the judicial branch (the courts) interprets the law. So the Supreme Court of the United States (acronym SCOTUS) is the ultimate interpreter of our country's laws. Justices are appointed by the President for life, and confirmed by the United States Senate.

The Supreme Court is asked to hear more than 7000 cases per year but it only hears about ~100 cases a year. The Justices carefully choose the cases they hear. Justices select cases based upon how important that case is to the entire nation. So the first thing to realize about the Supreme Court is that it is not the same as a typical court. 

There are two general categories of courts: state court and federal court. The Supreme Court rules over both of them. The state courts are much more common and decide most cases. You only go to federal court if there is a question about the Constitution or if two states disagree with each other. All lower courts have at least two appeals courts above them. And the ultimate appeals court over all of these courts is the United States Supreme Court. 

Most cases are heard in state court, such as "family" court or "traffic" court or "criminal" court. Federal cases are heard in "district" or "circuit" court. Each side can appeal to its next level. But most people don't realize that the appellate courts only decide if the LAW was interpreted correctly; they don't re-decide the FACTS. So to reach the United States Supreme Court, either two states disagree or one side thinks the Judges incorrectly interpreted the Constitution or a federal law.