Final answer:
Begin with tertiary sources such as encyclopedias to gain a broad overview when starting research following the GATHER model.
Step-by-step explanation:
When following the GATHER model for compiling sources for a research project, the type of sources you should read first are general reference works known as tertiary sources. These include dictionaries, encyclopedias, atlases, and yearbooks. These sources provide you with a broad overview of your topic, which is essential before diving into more targeted primary or secondary sources. Utilizing tertiary sources early in the research process allows you to gain a foundational understanding, helping to guide subsequent research and the development of your argument.