The Add-on is pretty easy to use. It requires you to provide a valid Genius.com API Key, which can be requested right from the Add-on itself.
Just follow the link after opening the popup and follow the instructions. You will be brought to a website with instructions how to set up the token.

Check out the FAQ on Genius!

Video How-To on YouTube:
https://youtu.be/0mlEESXl3LI

DISCLAIMER: Note, that this Add-on is UNOFFICIAL and I do not work for Genius or am affialiated with them in any way. I do not collect data or anything that relates to personal information.

The Add-on makes use of Genius API. The terms of service can be found here: http://genius.com/static/terms
Source code is available here: https://bitbucket.org/lars96/geniusbadge

Install

• License: MIT License
• Weekly downloads: 1
• Average daily users: 1
• Rating: 5/5 of 2 ratings
• Created: 2016-10-13 20:35:18
• Last updated: 2018-11-18 21:10:08
• Homepage: https://genius.com/Homesweethole-geniusbadge-browser-add-on-faq-annotated
• Support site and email
• Orig: https://addons.mozilla.org/en-US/firefox/addon/geniusbadge/
• API: @geniusbadge