If you are interested in understanding the relationships between pieces of information, the Branching note-taking format would be the most suitable choice.
Branching notes allow you to visually represent how different concepts and ideas connect to one another, making it easier to see relationships and organize information hierarchically. This format typically uses a diagrammatic approach, where main ideas branch out into related subtopics, fostering a clearer understanding of how various pieces of information interact.
While classifying can also help in understanding relationships to some extent, branching typically provides a more dynamic and visual way to explore those connections.