The Federal Government oversees the responsibilities of the nation as a whole.
By the dictates of the Constitution, the federal government was split into three parts, the Executive, Legislative and Judicial. Each of the branches were assigned specific rights and given rules for interacting with the other branches of government. This model is seen at the state levels as well because Individual states have their own constitutions which are similar to the national version.
Most people have been exposed to our system of government by learning about it in school and being exposed to it in our culture. However, sometimes the best way to learn information is to teach it. So now you will become the teacher.