Primary sources are first-hand accounts from the time period involved. They were created by someone directly involved in the events you’re studying, at the time of the event.
For example: diaries, letters, photographs, art, maps, original video, film or sound recordings, interviews, or newspaper articles
Secondary sources are created after the fact by individuals or groups who did NOT witness the events being discussed. They describe, analyze, interpret, report, or correlate the information about an event, thing, idea, or someone's life based on their study of primary material AFTER the events in question.
More about primary sources:
Remember, when searching for primary sources the language of our time may not serve you well. For instance, documents written during World War I would have referred to the conflict as "The Great War." The term "African American" is relatively modern in usage.
Primary sources are often biased. As you analyze them, try to understand the lens through with you view them.
(Thanks to https://sdst.libguides.com/c.php?g=690518&p=4883441)