Not only is it important to be able to create citations in your own work, it can also help you to be able to understand what a citation is referring to when you come across one.
For example, say your professor says you need this item:
Grendler, Paul F. The Universities of the Italian Renaissance. Johns Hopkins University Press, 2002
Would you look for it in the catalog, with books? Or in the databases with journal articles? In this case, based on the information that is included, this citation has told us that this is a book: Journal articles don't have a publisher (in this case, the publisher is John Hopkins University Press)
Maybe, while doing research, you come across this citation in another article's Works Cited list:
Davies, Jonathan. “Violence and Italian Universities during the Renaissance.” Renaissance Studies, vol. 27, no. 4, Sept. 2013, pp. 504–516. EBSCOhost, doi:10.1111/rest.12027
If you are familiar with citations, this you can recognize as journal article: Books usually don't have volume and issue numbers (vol 27, no 4). The "Article," in quotes, is published in the Journal, which will always have its title italicized
If this sounds confusing at first, that's ok--the more you cite, the easier it becomes.