A primary source is a document or physical object written/created during the moment in time you are interested in researching. A primary source provides information directly from the source (a book written by Adolf Hitler). A secondary source provides information indirectly (a historian's recounting of research done on Hitler).
American University gives an excellent guide to determine the differences between primary and secondary sources here.
What is EndNote?
EndNote is a reference management software that requires a subscription to use. Lucky for you, Roanoke College has a subscription. Create an EndNote account and keep track of your research, manage your bibliographies, and best of all, plug in citations as you write your paper. No more stressing over how to properly cite your sources. It's all done for you!
Marjory Collins. Reading lesson in African American elementary school in Washington, D.C., 1942. Gelatin silver print. FSA-OWI Photograph Collection, Prints and Photographs Division, Library of Congress (57C)