A primary source is an original document or account that is not about another document or account but stands on its own. For example, any novel, poem, play, diary, letter, or other creative work is a primary source. The data from a research study also constitutes a primary source because it comes straight from the participants' replies. If you were doing a paper on the emotional effects of job loss, talking to someone who just lost their job would be about as close to your topic as you could get. That's what we mean by distance.
Secondary sources are ones that interpret primary sources or are otherwise a step removed.
A journal article or book about a poem, novel, or play or a commentary about what an interview signifies is a secondary source. Your paper will likewise become a secondary source. Try this Exercise on Primary and Secondary Sources from SUNY Empire State College Writer's Complex. Not all assignments ask you to consult secondary sources. For literary essays in particular, often all the examples or evidence you need will, and should, come straight from the text.