How do I edit script under my Avatar?

[ApriliaNut]

In the dictionary under computer illiterate you'll find me. With this new platform [? is that the correct term?] I was able to fumble around and edit my signature but for the life of me I can't figure out how to edit undermy avatar. The mileage has certainly changed and I want it to be more accurate.
So can anybody point me to how it's done?

Thanks