Using Colorbox without a plugin

Hey

I have been working on getting multiple jQuery lightbox plugins to work in WordPress without having to use a WordPress plugin.
I found a tutorial on Fluidbox: https://sridharkatakam.com/medium-like-fluid-lightbox-wordpress-using-fluidbox/

Got that working. I am now trying a similar method as used in the above post with Colorbox, but am not getting it to work.

What about making a blog post showing how to use Colorbox without the plugin?
So a person can choose which method to use Colorbox.

Thanks.

https://www.ads-software.com/plugins/wp-colorbox/