How to make this comments.php code for nested comments

I am trying to implement this (https://www.cssbake.com/cookbook/icondock-the-ultimate-web-2-0-comments/) comment styling on my blog (https://techlunatic.com)

It is working fine but it has no provision for nested comments option. I did read other tutorials in and outside the forum (https://support.slightofmind.net/topic/nested-threaded-comments-and-styling), but don’t know how to make it work for my code.

Any help would be appreciated