Zotero can be accessed online or via a desktop client. Note that the desktop client is more powerful and offers greater functionality than the web version. However, if you are using a Google Chromebook, you will not be able to download the desktop client.
To create an account, download the desktop client, and/or install the Zotero connector to your browser, visit Zotero.org.
Your collected resources are stored on your web account and/or desktop client. Remember to sync your Zotero account so that you can access your resources from anywhere.
Don't forget to install the word processor plugin. This will enable you to integrate Zotero with your word processor so that you can easily cite your sources in the text or in a bibliography.