Strategies on finding peer reviewed articles for intro level reseach

student x is in a generic intro class and x student is asked to write a research paper on any topic related to the field. Furthermore, professor y shows student how to generally use a databases and how to identify academic papers that are peer reviewed. However, in my experience professor tend not to give strategies on finding research that is not potentially overwhelming to students/intro researchers. For example, student x for into psych research paper on how tau contributes to Alzheimer's (assume student x does general research on topic) and as you can probably guess the papers require a fairly high level of knowledge to understand. Ultimately, how does student x find research that they are appropriately suited to their level of knowledge of the topic.

Also, to broaden this question a bit more I think it would be more than appropriate to include professor y's perspective on this topic. For example, why this particular element is left out and so forth.