A primary source is a document or object that was written or created by someone who was a participant or witness to the event. Examples of primary sources include diaries, letters, speeches, autobiographies, news footage of an event as it happened, or artifacts. (Yes, artifacts, such as pottery, or a quilt.) Ask yourself, "Did the writer or creator witness or experience the event?"
CCGA librarian Lynda Kennedy has a handy chart that will help you determine if your document is a primary source.