- Download the tarball from the Groovy Emacs Mode page on Launchpad.
- Extract the content of the downloaded tarball to your ~/.emacs.d file (for Linux, Unix and Mac OS X), whatever the equivalent is for Windows.
- Update your ~/.emacs.d/init.el or ~/.emacs file as needed to set up the appropriate autoload configuration. See "Setting Up Emacs" below.
- Restart Emacs if it is already running.