QuickSearch, the search box at the top of the Libraries homepage, searches across a wide array of library resources, many (but not all) of the databases, ebooks, plus the libraries physical collections, print books, government documents, etc.
You can search for a specific book, article, etc. by simply searching for the first several words in the title in "double quotes": "engendering the black freedom struggle." The item should show up at the top or very near the top of your search results.
You can click on Advanced Search and select the the Author field from the drop-down menu next to Any field. Type the name of a party leader, last name first, in quotes: "cleaver, kathleen". This will retrieve all the books, articles, etc. that Cleaver wrote and that Rutgers has print or online access to.
Also in Advanced Search, you can limit your search results to primary sources. In the drop-down menu to the right of Any Field, select Subject and search for:
sources OR archives OR correspondence OR diaries OR speeches OR interviews OR oral OR newspapers
Make sure to use the caps. QuickSearch won't search properly if you use lower case. Then enter search terms below that relate to the topic of your paper.