Get some background information and context on the topic. Begin collecting keywords and related concepts.
Start getting a little more strategic about sources.
At this same time, I am getting more strategic about by search terms. What concepts does the Mundaneum represent? What additional information can I find if I use these search terms too, or instead of, my original terms. For example:
What is the Mundaneum? It could be called a World Palace, World Brain, a Knowledge Archive, a Knowledgebase, an Early form of the Internet
How is the Mundaneum organized? Controlled Vocabulary, Bibliographic Control Systems (broader term), Universal Bibliography Control System (used by the Mundaneum) Dewey Decimal System (related term)
Who are the people involved? Directly involved: Paul Otlet, Henri La Fontaine, Played a part: Dewey, Le Corbusier. ...