You want a document relevant to your topic. You may use an article or book that your professor has assigned in order to find related works. Ideally your seed document will be important in your field so that it leads you to a wide body of related works.
Citation chaining is a research technique in which you use one source, called a seed document, as a way to find related documents.
There are two types of citation chaining:
Citation chaining can help you trace back to the roots of important ideas or movements or start from the beginning stages and see how things grow. It's also useful for finding related documents on a topic.
One of the unique features of Web of Science is the citation maps it provides. These maps give you a visual representation of the impact of a particular work, either forward, backward, or both.
Backward and Forward mapping