When writing a paper or creating a project, you need to cite everything that you did not write or create yourself. This includes articles, books, maps, videos, statistics. Citing your sources means that you follow a specific format to show what source you used.
Below are some examples in APA format:
Citing an article: Kim, D., & Ra, Y. (2015). What impacts success in college? Findings from the perceptions of Korean students. College Student Journal, 49(1), 161-168.
Citing a book: Santrock, J., & Halonen, J. (2010). Your guide to college success: Strategies for achieving your goals (6th ed.). Boston, MA: Wadsworth Cengage Learning.