Purdue Online Writing Lab (OWL) has a series of videos about using MLA style for your paper.
You can manually enter and save your information sources ("citations") in Microsoft Word, and then add citations while you write, and add a works cited/reference/bibliography list at the end. Click here to see a brief video showing you how to do it.
ZoteroBib (or Zbib) is a free web service that helps you quickly create a bibliography in any citation style, including Modern Languages Association (MLA). Zbib retains all the citations you created using the same device and browser, so you can store all the items that should be listed in your works cited/reference/bibliography.