With a large multi-term project like your senior project, it can be helpful to use a tool that not only cites sources, but helps you keep them organized. Zotero is a free, open-source tool you can use to keep track of the sources you find, organize them, and create citations.
To get started, you'll need to download both Zotero and the Zotero Browser Connector. Both downloads are found on this webpage:
APA Style Guide from OWL
The OWL at Purdue has an excellent guide to using the APA style, including creating citations, formatting your paper/project, and more.