Where you should search depends on the type of information you need.
Background information includes dictionaries and encyclopedias. Search these resources when you want the basics: definitions, descriptions of what something is, etc.
Books contain both basic and in-depth information. It depends on the book. A book about Argentina might describe basic history and culture while a book about tango music in Argentina might be more in-depth.
Articles are good for in-depth information and research. Typically, they are not good for basic information.
Videos contain information about various topics and provide ideas for search words.