Imagine having to know all this in complete detail...

Here's a interesting website: Presidential Transition Resources

This is the official introduction to what's contained within the site:
The Presidential Transition Act of 2000 (P.L. 106-293) authorizes the General Services Administration (GSA) to develop a transition directory in consultation with the National Archives and Records Administration (NARA). The Act provides that the transition directory "shall be a compilation of Federal publications and materials with supplementary materials developed by the Administrator that provides information on the officers, organization, and statutory and administrative authorities, functions, duties, responsibilities, and mission of each department and agency." Senate Report 106-348 clarifies that the directory is intended to "assist in navigating the many responsibilities that fall on a new administration" that is "confronted by an overwhelming amount of material."

What that means is:
Every president-elect gets a "study-packet" of all the governmental branches, departments and agencies (who heads them and what they do) as well as how they fit into the overall umbrella of our government.

There's A LOT of info contained in this website... A LOT! This site would be a great help to anyone doing a paper or project on this subject.