To download and install Zotero, visit https://www.zotero.org/download/
You must download and install two components:
For help installing Zotero after download, see the Zotero installation page.
Register for an online account at https://www.zotero.org/user/register
Online accounts are free. You don't need an account to use Zotero software, but it allows you to join groups and sync your library across multiple devices.
To link Zotero software to Zotero online and sync your data, open your Zotero Preferences > Sync > Settings. Then sign in with your account details.
Once installed, display options can be changed in the middle panel.
Remember to regularly back up your Zotero library. Don't rely on online syncing. Save a back up file to a USB or external storage device.
To make a back up of your Zotero library, make a copy of your Zotero data directory.
This is located in Zotero Preferences > Advanced > Files and Folders > Show Data Directory.
To create a back up, close the Zotero and copy everything in this folder location. Then save to a storage device.