Suppose your professor gives you the following citation and tells you to find the article:
Montague, M. (2017). Perception and cognitive phenomenology. Philosophical Studies, 174(8), 2045-2062.
Try using Primo (the library catalog) to find it:

If we do not have access to the article, you can request it from another library. The process often takes less than 24 hours.
What if I don't see my article? Primo initially gives you articles results that are available full-text, but if you don't see the article you need, just click "Expand your search."

If you then see your article, you can request it.

If you still don't see it, don't worry. You can use the blank request form to submit a request.