How to change the WebGL Loading Screen?

Hi guys,
I'm looking to make a loading screen like this:
https://ocias.com/games/the-yearning-tree/
And I wanted to follow this guide by making my own template, but I think it's super outdated. UnityProgress.js doesn't even exist anymore, I don't see it's in the Minimal template, now it's UnityLoader.js and full of encryption stuff:
https://ocias.com/blog/unity-webgl-custom-progress-bar/
It looked like a good guide but I think it's not useful anymore at all.
My main concern is changing the Unity logo above the loading bar into my company's logo, but being able to show the numbers and stats like The Yearning Tree would be fantastic.

 

try Default template (not minimal)

unity editor's path of template to copy and see \ change:
Unity 2019.1.0a12\Editor\Data\PlaybackEngines\WebGLSupport\BuildTools\WebGLTemplates\Default

in 2017 I have successfully tested my WebGLTemplate with custom preloader with my html + js.
In 2019 it's still there.

for your special case of Logo you can change only CSS or rename your logo to unity'