A primary source is a document that was created during a particular time period. This may include first-hand accounts of historical events and time periods, such as speeches, diaries, letters, and news coverage. Creative works such as fiction, poetry, and art are also considered primary sources.
A secondary source is about a primary source. It analyzes, interprets, and comments on the rimary source. Books and scholarly journal articles are secondary sources.
Hamlet is a primary source. It was written during the Renaissance. Harold Bloom's Hamlet : poem unlimited, which is a book about Hamlet, is a secondary source. It was written in 2003.
A letter from a WWII soldier to his family is a primary source. A journal article about WWII soldiers and their families is a secondary source.