According to Product Design, a concept map, or mind map is a diagram used to represent ideas linked to, and arranged radially around, a central key word or idea.
Mind mapping involves writing down a central idea and thinking up new and related ideas, which radiate out from the center. By focusing on key ideas, and then looking for branches out and connections between the ideas, you can map out your knowledge in a manner that will help reframe your knowledge.
When you take the time to concept map your topic, you're breaking your research into smaller, more manageable parts.
In my example, the the transportation ghetto of Theresienstadt in Czechoslovakia is the main topic or focus. From there I can brake my topic into smaller, more manageable pieces. In this example I could choose to investigate any of these subtopics for my project.
For the sake of this research example, we will be investigating the propaganda aspect of the Theresienstadt transportation ghetto.
Your concept map can also serve as a rough draft for your essay outline.