Have you found some material? If you found them through the library, they're probably going to be good sources. However, it's always important to evaluate your sources to ensure that they are credible. Not sure if a source is credible or not? Consider the following factors:
Does your source check out? If so, great! If not, you might want to look for sources that are better suited to the assignment.
Once you've evaluated your sources it's time to start working on your assignment, and then you can move on to the Final Step: Cite Your Sources.