The techniques are the two sub-pages are not intended for undergraduate research. They are intended for faculty and for some Masters level research. They two techniques are intended to help you discover more items related to your research.
In "Citation Tracing" the idea is to trace an idea through the history of the literature. You start with the original article/author and then find other articles that cite that original. You then follow the argument through successive generations of scholars and articles.
In "Similar Bibliography" the idea is to find articles that have either similar bibliography entries or to find articles that have similar subject headings.