Reference materials, whether online or in print, normally fall into the following categories:
Indexes and Abstracts
Manuals and Handbooks
Subject Specific Resources
You will want at least a passing familiarity with each of these types of reference resources. Depending on their purpose, they can vary drastically in what they have to offer and how they can help you. The only way to know where to get the help they offer is to go to the library and look through them.
This section of the course, therefore, will require that you go to the library and learn the differences between the various reference materials. Get your hands on the books, open them and find out how one varies from another. One biographical source may cover only dead people, another only living people. One dictionary may tell you how to use a word, another may not.
Having said that, let's begin with the encyclopedias...