A citation manager can help you keep all of your research organized and manage all of your references and PDFs. It will also help you easily insert citations into your paper as you are writing and it will automatically format bibliographies using whatever output style you need.
There are a number to choose from and to help, this comparison chart to help you decide which one might be the best fit for you.
UW-Madison General Library System Subject Guide on Citing Sources. This guide goes in depth about citation managers, and the variety of different citation styles available: http://researchguides.library.wisc.edu/citing
Ebling Library's subject guide "Citation Managers" specifically describes your options and presents videos to learn more about the manager, how to utilize it and instruction materials. http://researchguides.ebling.library.wisc.edu/citation-managers