1 Install the CVS build version of Stepmania. Download it below.
Stepmania CVS Windows build
Stepmania CVS Macintosh build
2 Unpack the Groove 2.x theme into the "Themes" Directory inside the Stepmania CVS directory.
3 Unpack the optional Noteskin into the "Noteskins" Directory inside the Stepmania CVS directory. Delete the old "dance" directory and rename the new noteskins folder to "dance".
4 Launch the Stepmania program and choose "Options"
5 Choose "Appearence Options"
6 Next to the "Theme" option, switch from Default to Groove 2.x
7 Choose exit and enjoy your new theme!