Citing the sources of information you used is not really hard; it just takes a bit of time. There are many different citation styles, but most students need to learn to follow the conventions of MLA or APA. Style guides are about more than just citing sources of information or ideas. Guides can help you improve the style of your writing and avoid bias, for example.
Any citation you provide should enable your reader to find that source. Make sure your citation gives the reader the information they need to find the source you used.
Most of the major style guides (MLA, APA, etc.) can be found at Pace University's Campus Libraries. Information you need to locate the style guide books (call numbers and locations) can be found here. Look for the Call Number, which is like the address of the book. Ask at the Help Desks on the 4th or 5th floor if you're having trouble finding a book.