Code Training

Can you narrow that down to what you want to learn specifically?

Have you had a look at https://wordpress.tv/ ?

Yes, I’m wanting to be able to create my own plugins and/or widgets and gain a better understanding of Wordpess at the code level.

The most basic example of what a plugin is, is to look at the Hello Dolly plugin that is bundled with every installation

there are also a bunch of plugin frameworks that might be instructive

https://www.google.com/search?q=wordpress+plugin+frameworks

and check wptavern.com