- Making Firefox the default browser is already covered in How To Make Firefox The Default Browser.
- Managing different file types is already covered in Managing file types.
- Searching the web is covered in Search bar.
- Tabbed browsing is covered in Tabbed browsing.
Other than that, the title does really tell us what the article is supposed to cover. Much of it seems to cover the very basics. Looking at the rest of the content:
- Navigating web pages - "Viewing your home page", "Retracing your steps", and "Stopping and reloading" seem like good info for a "Firefox Basics" article. If the user has found this article, then it's logical to assume the user already knows how to "Navigate to another page" or "Clicking a link" (which are the second and third parts of that section). If that content were to be included, there should be a help-topic link pointing to it.
- Using the Sidebar - I don't see the usefulness of the content in that section.
- Searching within a page - I think this would make a great separate article. I think it's a common use-case, and a great chance to educate users about FAYT. bug 481475
- Copying part of a page - This one, I don't know about. I have no idea if that's a common use-case.
- Saving all or part of a page - This could make for a good separate article. bug 481480
- Printing a page - This seems good for a separate article. There's certainly enough content. bug 481483
- Changing cache settings - IMO... monkey content.