The subtabs under this page are all lists of digital collections, many open-source and free to search on the web. The collections are gathered together to help you on the start of your research; every collection will have multiple sources listed. Remember that you will have to cite each individual source and NOT the collection! If you find three sources in the Library of Congress Digital Collections, each of those three sources need their own listing on your Works Cited page as well as individual in-text citations when used in your project.
You can use the general primary source list as a starting point for ideas if you like, or to search for specific topics in that general source on your own. Browsing through the sub-collections that sites have to offer may help you brainstorm an idea or to locate a source that isn't listed under the topical collections. Many of the collections listed there will also have sub-collections relevant to the topics listed in other tabs; for instance, the Library of Congress's collection has a subcollection called "Americans React to The Great Depression"; this collection will be listed under The Great Depression tab while access to the entire Library of Congress archive will be in the General tab. However, since not all of the smaller collections found within the general collections will be listed under one of the specific topical lists, you may want to try searching the general sources to see what you can find.
When you have an idea of where you want to focus your research, you can search through the primary source listings under the appropriate subtab. Some subtabs are large concepts that may have smaller concepts broken out; for instance, Politics in the Gilded Age will have a section devoted to the Presidents and elections of the time, some of the scandals that led to reforms later, amendments of the era, etc. By dividing the broader topic into smaller ones, it may help you choose a topic, but it also helps guide your research path.
Remember that you are ultimately responsible for your research. While this guide may help lead you to sources, it is completely up to you to decide how to use it and its resources.