In the days before I used Zotero, I allotted at least an entire day of paper editing to add and perfect the footnotes and references. Zotero's greatest advantage is that it streamlines this process—one can insert already perfectly-formatted footnotes and references on the fly with the help of the Zotero Firefox browser and word processor plug-ins. This vastly simplifies and expedites collaborative work that draws from a number of sources. The "network effects" of Zotero had been a negative aspect of the application for collaborative work in the past—very few people worked with it and developed it, and thus it was buggier and harder to use with groups—but over the last few years this has changed. It is now the most popular and developed application for citation work "on the market". The fact that it is a "free and open source" application, means that it is free to use and relies on no API, so it will never be shut down when a corporate application to which the API manages access updates or shuts down. The open source nature of the application also allow a number of related developed plug-ins and add-ons to do about anything anyone envisions. For example, there are a number of additional plug-ins that allow for easy citation analyses. The application also has the ability to synchronize across devices, provided that they are desktop/laptop devices, with a single sign in username and password. This further facilitates the ease of use and collaborative nature of the applicaiton.
The drawbacks of Zotero are that while the project is open source, a number of the plug-ins can be buggy. It does not work with any browser but Firefox, which is itself increasingly buggy. It does not work with mobile and tablet devices.
To get started with Zotero, navigate to https://www.zotero.org/ in a Firefox browser and follow the prompts. Be sure that your word processing application is not open and running when you do this so that the plug in successfully updates to your word processor when you open it next. There are many tutorials online to get you on the way to successfully using Zotero. I suggest this tutorial by UCLA library.