If you want Firefox to do those things, click Use Firefox as my default browser. That means, when you open a link in your mail application, an Internet shortcut, or HTML document, it will not open in Firefox. Upon installation, Firefox will not be your default browser, which you'll be notified about. Because you download Firefox from the official site, click Open. When you first start up Firefox, you will be warned that you downloaded Firefox from the Internet. Just click on its icon in the dock or Applications folder to start it. Just open your Applications folder and drag Firefox to the dock.įirefox is now ready for use. Tip: You can add Firefox to your dock for easy access. Do not run Firefox directly from the Firefox.dmg file or drag the icon directly to your desktop to install, as this can result in issues such as lost data and settings. Complete the steps above before running Firefox.