Zotero is a citation management tool. You can use it to "bookmark" your sources and organize your research.
Zotero has a fabulous documentation site that will answer many of your questions about using Zotero.
Alternatively, feel free to make an appointment with a librarian:
Zotero has three main pieces that you have to set up before you can run wild saving your research.
1. Start at zotero.org
2. Select Download.
3. Download Zotero 5.0 (make sure you select your correct operating system). Follow the installation instructions.
4. Then go back and download the Zotero Connector (select the connector for your preferred browser). Follow the installation instructions.
5. After you have installed both Zotero 5.0 and the browser plugin, return to the website and register for a free account.
6. After you have registered for a free account, open Zotero 5.0 and then open the "preferences" dialog box.
7. The Sync feature will allow you to link your downloaded application with your cloud-based account--so that you can access all of your sources from any computer.
Zotero allows you to collaborate and share sources with other people through the use of Groups. You can create a group, invite people to it and then everyone can add sources to the Group library.
Zotero also integrates with Microsoft Word and Google Docs. After you have installed Zotero, open Word (or restart it if it was already open) and there should be a new menu/ribbon (depending on your operating system) labeled "Zotero". This gives you the capability to include citations directly from Zotero and Zotero will attempt* to format them for you (in your chosen style).
*Disclaimer: Zotero's ability to make accurate citations is 100% dependent on the quality of information in Zotero. You can edit your sources in Zotero to include better citation information, if needed. It is still your responsibility to cite your sources appropriately.