If you do not know anything about Firefox, read on
What is Firefox?
Firefox is the fast new web browser which is making the web fun and easy again. A web browser means a program used to surf the internet, like the Microsoft Internet Explorer (IE).
Firefox is free! Through the unique development methods of Open Source, they are able to make a product with impressive speed and less errors than programs developed by traditional methods. It has a number of unique features, and it is overall a great product.
Firefox received amazing reviews and created a lot of buzz on the internet. Within a few months, millions downloaded it, and by mid-2005, Firefox captured more than 10% of the Web browser market. Many view it as a safer and a better alternative to the Internet Explorer (IE).
For more information, visit the Mozilla Foundation.
See the Firefox Wikipedia Page for more details: http://en.wikipedia.org/wiki/Firefox
Getting Firefox installed on your computer is your first step to using it.
An Introduction and installation guidelines for Firefox explained well here: http://opensourcearticles.com/introduction_to_firefox
Extend and Customize
Plugins have traditionally been part of the browser environment, for such tasks as watching Flash movies or viewing PDF documents. Something different has evolved in Firefox, and that is the Extension Manager.
To access the extensions of firefox, go on Tools -> Extensions. But the term Extension Manager is used in a more general way. Extensions are packages that you can install into Firefox that add a new feature to it, to make it do much more than it can, or to improve the overall look and feel. There are many add-ons you want to explore, and select according to your need.
The architecture of Firefox, by being standards-based and open, is ideal to such customizations. You just need to look at the categories on Mozilla Update to get a feel for what else is out there.