Custom Trailing cursor with animation

I followed a YouTube guide but it's old and not getting a response. He said either CSS or JS

https://codepen.io/designcourse/pen/GzJKOE 
In order for the code to work, do I need any additional elements besides the CSS code in the middle block of the url displayed above?

I uploaded the CSS code plus an image, eg a black dot for the cursor (where the code says //cursor: none; ) and all I get is a black dot.  If I take out the black dot url, I get no change.

I am clearly missing something. Working on 7.1

The cursor displayed at the bottom of the screen is exactly what I want to achieve.

Your Codepen uses SCSS, but Squarepace support CSS or LESS only

You can convert it to CSS first