Training yourself in WordPress development can be an overwhelming task:
the more I am able to talk to people in the community, the more I realize that people simply don’t understand the concept very well, or at all.
The simple fact is that a lot of WordPress documentation is written by developers, for developers, and it’s assumed that the reader has a certain level of experience in reading technical documentation as well as in writing code for the WordPress platform. That assumption leaves beginners and pre-beginners often struggling in trying to understand “the big picture”.
If I were going to teach an Intro to WordPress class, I’d likely start where Nathan Rice did: with Action Hooks. They really are the foundational element of WordPress development, as it truly is impactical to develop for WordPress without using them. They are the basis of themes, plugins, admin panel mods, user permissions… basically, everything.
Check out Nathan’s article on action hooks if you’re looking for a solid explanation.