Paraphrasing is when you do not directly quote someone else's words, but use your own words to communicate their information and ideas. Paraphrasing is similar to summarizing, however summaries only include the essential ideas of a work, while paraphrasing includes more details.
Since your paper should only use direct quotations sparingly, you'll be paraphrasing frequently. Just remember that you still need to express plenty of your own ideas. Use paraphrasing to support those ideas, and be mindful that you still need to cite paraphrased portions of your paper.