A secondary source is one that was created after the event by someone who wasn't there. Examples include books, journals, magazines and websites. It isn't one that is secondary in importance!
For your paper you need to find scholarly sources. The slide below tell you the difference between a scholarly and non-scholarly source. If you're not sure, ask your teacher or a librarian.
How do you know if an article you find is scholarly? Look at the chart in this presentation to help you work it out. Make sure you are looking at an article NOT a book review (though you can look for the book if it sounds worthwhile). If you're still not sure, ask a librarian or your teacher.
These databases are available through the San Francisco Public Library. You will need your library card and PIN. If you have lost one or the other check with the UHS librarians.
Here's a quick video on using the SFPL databases above.