Try one of these articles:
- Make Firefox your default browser Make web links open in Firefox automatically by setting it as the default browser on your computer. This article explains how to do that.
- Customize Firefox controls, buttons and toolbars Firefox is easy to customize. Put your favorite features right where you want them. We'll show you how.
- Learn more about the design of the new Firefox Firefox has a new streamlined interface as well as features to make it more efficient and easier to customize. We'll look at the thinking behind these changes.
- How to sync your add-ons with another copy of Firefox This article contains steps for enabling add-on synchronization across devices.