First, you’ll need to install the Ubiquity extension.

After you install the extension and restart Firefox, you’ll be taken to a page with a link for an interactive tutorial. Click on that and then follow the tutorial’s instructions; it will explain how to use Ubiquity and several of the most useful commands.

When you’re done with the interactive tutorial, you can learn more by taking the more in-depth User Tutorial on the Mozilla Labs wiki. The main Ubiquity page on the wiki has links to many other useful informational resources as well.

If you have questions or problems, you can take them to the Ubiquity-firefox mailing list/discussion group or to the Ubiquity IRC channel on irc.mozilla.org. Most of the developers hang out here and are happy to answer questions.

If you are looking for more Ubiquity commands, you can browse through Browse Commands In The Wild, a wiki page that lists commands written by other Ubiquity users. We make no guarantees about any of them, but you are welcome to install some and try them out.

Finally, if you are interested in learning how to write your own Ubiquity commands, read the writing commands page.