To install the free Firefox web browser:
Open another web browser (Internet Explorer is the default that comes with Windows).
Go to: www.mozilla.com.
Download the free version of Firefox to a temporary location. There is no need to store the installation file permanently because if you have to do a re-install, you will always go to the web to get the latest version.
Run the downloaded install file to install the browser.
Check the Free Software section to install useful extensions to Firefox.