You need to place this file in your scene directory. You will need to customize at least two things in the code:
https://cdnjs.cloudflare.com/ajax/libs/webicons/2.0.0/webicons/webicon-facebook.png is an URL of the icon added to the menu.
Last part of https://www.facebook.com/sharer/sharer.php?u=https%3A%2F%2Fdemo.shapespark.com%2Fsofa-facebook-share is an URL that is shared on Facebook, so you will need to change it to your scene URL (%2F needs to be used instead of /, %3A instead of :)