The document summarizes the structure and roles of the lower federal court system in the United States. It outlines that there are two types of lower federal courts - constitutional courts and legislative courts. Constitutional courts include district courts which handle trials, courts of appeal which hear appeals of district court cases, and the Court of International Trade. District courts are located throughout the country and use both grand and petit juries. The majority of federal cases are handled in district courts. Courts of appeal further review district court decisions and can affirm, reverse, or remand cases. Legislative courts are created by Congress to help exercise specific powers like taxes and military affairs. Judges are appointed by the president.