Primary sources are original documents and objects which were created at the time. Typical examples include letters, diaries, photos, newspaper articles, eyewitness accounts, autobiographies, government reports, paintings, maps, etc. In actuality, it can be more complicated and can depend on the topic/time period.
Always clarify with your professor.
Browse footnotes and bibliographies of books, encyclopedias, and articles for information about primary sources.
Search the Library Catalog for primary sources--both unpublished manuscripts and modern editions in print and online, sometimes in translation, of original primary sources. Use the "advanced search" with the terms for primary sources below as subjects, not keywords.
Library catalog/database terms for primary sources:
Sources means primary sources in a library catalog. It can mean a printed, edited, modern edition of an archival source; or it can mean a collection of excerpted, translated sources which might have the words "reader" or "documents" in the title; or it can mean a book about primary and secondary sources. All are invaluable. The footnotes and bibliography of any of them will lead to more sources.
Bibliographies are whole books devoted to a topic, usually a broader topic such as "Vietnam War" or "Early Modern Europe." They are a list of sources, often primary and secondary, generally described and annotated. Extremely helpful for getting a handle on sources and the scholarly literature on a topic.