It is important to cite your work. Plagiarism, even if unintended, is serious. The tutorial in the left sidebar provides details on how and why to cite.
There are many free tools you might use such as KnightCite, Citation Machine, and Easy Bib. In Microsoft Word 7 (and later versions), click on 'References' in the top menu and choose 'APA' in the drop down menu. 'Insert citation' or create a bibliography/works cited page.
If you find articles through the library databases, look for the [Cite] button on the right hand side of your screen after you open up the article.