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Zotero works for Windows, Mac and Linux operating systems.
Installing Zotero is easy and free. Just visit the Zotero website and download the right version for your computer. Installation instructions are available on the Zotero Website.
Download Zotero desktop version for Window or Mac or Linux
Download Zotero Connector
You will also need to download the relevant browser connector in order to get the full functionality of Zotero. Open Firefox /Chrome/Safari/Edge, go to the Zotero Download page, install Zotero Connector.
Zotero online account: it is also a good idea to register and create an account with Zotero. This allows you to back up your library to Zotero's cloud-based servers.
Storage
The storage of your desktop Zotero is unlimited.
Free online storage is 300MB. Additional storage data can be purchased.