If you aren't sure if you need to cite it or not, go ahead and cite it.
... directly quote from a source?
... paraphrase from a source?
... summarize a source?
Plagiarism is taking someone else's work and claiming it as your own.
Plagiarism 2.0: Information Ethics in the Digital Age. Films Media Group, 2011. Films On Demand. Web. 28 August 2013. https://proxy.campbell.edu/login?url=http://fod.infobase.com/PortalPlaylists.aspx?wID=103991&xtid=43790.
The following tutorial was created by the librarians at the University of North Carolina - Chapel Hill.