Federal Court System
Works like a machine
District Court
All of the cases begin here, the lowest level of the federal court system. These have original jurisdiction, which means they have the right to hear a case for the first time. Here a jury is used to decide if the accused is guilty.
Appeals Court
If somebody is unhappy with the ruling of the district court they may bring it to attention to the Appeals court, who had appellate jurisdiction, meaning they can hear the District courts ruling. The main job of the Appeals court is to decide if the District Court trial protected their rights, and it was fair. They then can decide if the ruling is okay or not, and if not they can remand it, or send it back to be tried again in the District Court. Each Appeals court has a circuit that they tend to, their set geographical area.
Supreme Court
If there is still debate about the ruling, they can bring the case to the Supreme Court, however they only take on 100-150 cases per year (out of about 7,000). There are 9 Supreme Court judges (or justices) who are appointed by the President and approved by the Senate. They are then committed to a life term, meaning they are only subject to impeachment, they cannot be fired.
US Marshall
In charge of arresting, taking convicted to prison, and collecting fines. Helps keep order in the courts and serve papers.
Magistrate Judges
Mostly routine work, like issuing warrants, or bail.
US Attorney
In charge of a lot of paperwork, and ensures the court runs smoothly.