The federal court system has three main levels: U.S. District Court, U.S. Circuit Court of Appeals and the U.S. Supreme Court. Each level of court serves a different legal function for both civil and criminal cases.
The U.S. District Court has jurisdiction over cases involving both civil and criminal actions. Civil actions must arise out of a violation of one's constitutional rights, a violation of law or treaties of the United States or if the United States is party to the suit. Civil maritime cases and cases involving citizens of different states are also heard in district courts
The U.S. Circuit Court of Appeals resides over cases in where one or both parties are dissatisfied with the judgment in U.S. District Court. The lower court ruling is reviewed by a panel of three judges to determine whether there was an issue with the application of law. The U.S. Circuit Court of Appeals hears both civil and criminal cases.
The U.S. Supreme Court is the highest court in a state or in the United States and generally only deals with matters of state or national importance or appeals from the appellate court. This court will take cases from appellate court only if there is an issue with the interpretation of the law or with a constitutional right. It is also the last step in the appeals process. There is no appeals process if either party is not satisfied with the decision
Sorry it's so long, but I hope it helps!:)