Creating an account on the Zotero Web site allows you to have a copy of your library on the Zotero server, very convenient if you are not always working on the same computer or for collaborative work.
After creating your account, enter your username and password in your Zotero preferences: select Preferences in the Edit menu, then Sync., enter your username and password. You have to repeat this configuration on each of your computers. The synchronisation is then done automatically after each change in your database.
You can sync an unlimited number of references, notes and collections. PDFs and other attachments take up storage place, which is limited to 300 MB for free. You can purchase additional storage space if necessary.
If you want to save money you can:
- uncheck the option Sync attachment files in the Sync tab of the Preferences pane.
- instead of attaching the pdf file to your reference, attach a link to the file that you will keep on your computer or online.
- store your files on an external server (all technical informations here). You can find here a list of storage services which work well with Zotero.