When using information found in a resource, be sure you are giving credit where credit is due. Whether you're paraphrasing or directly quoting, you need to add a citation in for any element you did not previously know prior to reading/using that source. In doing so, you are honoring the idea. This means, even if you put it in your own words, you need to cite it.
More information on quoting, summarizing, and paraphrasing: