Please note: Zotero has just released a new standalone version, Zotero 5.0, which will replace all previous versions, including the Zotero Firefox plugin. See the Zotero.org blog post about the new version. Users of the Zotero Firefox extension can download the Firefox connector from the Zotero download page, along with the new version.
Zotero Standalone runs as a separate application and plugs into your choice of browser. Standalone has connectors that work with Safari and Chrome browsers as well as Firefox.
You can not have Zotero in Firefox and Standalone open at the same time. You must have Zotero Standalone open to use the Chrome and Safari capture icons. (If you don't you will just be redirected to Zotero's website.)
You do not have to install the word processor plugins with standalone. The plugins are bundled with the software download.
To install the Zotero Standalone software visit http://www.zotero.org/download/. Click on the link for the correct operating system and follow standard procedures for installing software on your computer. Zotero Standalone comes with word processor plug ins, so you will not need to install these. Links to install the Chrome and Safari connectors are found just below the Standalone download links.
Chrome Connector - A box will appear in the lower right hand corner of the browser asking if you want to continue. Click Continue. Then click Install when Chrome asks if you want to install.
You will now see Zotero capture icons in the address bar just like in Firefox.
Safari Connector - Depending on your settings Safari may not automatically open the file. Use Control+ Click and select "Download linked file to..." to save the file to your desktop or some other easy to remember location. Double click the file to open. Click Open, then click Install. The Safari capture icon will show up as a little box to the left of the address bar.
Getting Zotero: Installing Firefox extension.
To install the Zotero extension in your Firefox browser, visit http://www.zotero.org and click the red download button.
If your pop-up blocker is enabled, you may see a yellow bar at the top of your browser telling you that Firefox has prevented the site from installing software. Click Allow
Word Processor Plug-in.
An additional word processor plug-in is needed to insert and format citations in Microsoft Word or Open Office documents when using the Firefox extension. The plug-in you install depends on your operating system and word processing program. To find and install the right plug-in and extensions for your word processor, visit http://www.zotero.org/support/word_processor_plugin_installation
Once you have successfully installed the plug-in, you will see the Zotero citation tools right in your word processor.
Here is an example of what the Zotero plug-in looks like in Word 2007.