The Anthem editor is the least commonly known-of editor in Spore, where the player can edit their nation/empire's Anthem. It is found solely in Civilization Stage and Space Stage. To adjust notes in it, you can slide the note shapes up and down. You can also choose your instrument, beat, and add ambience of your choice limited at four. You may scroll up or down to change the note's length, from a sixteenth note to a full note.
If the note appears orange or red, then that note is musically "off" and does not flow well, but certain themes need that. Yellow notes may sound slightly off, and green means the note flows well. You can also add notes with the button in the anthem editor that has a note with a '+' sign over it, and vice versa with the note that has a '-' on it.
To find the editor, find a city in Civilization stage or Space stage and go to the option that has a helmet (At the top) and from there you can see it.