Welcome to MIDI Tutorials. Sorry, I was a bit slow to acknowledge your introductory post.
As you can see from Andy's post, the idea is to gradually read through the articles and ask questions if they don't make sense. For most people from a non-computer programming background, understanding MIDI can take a little time. This is quite normal. I was lucky in that Istarted with computers way back in 1966, before they even had a keyboard for input.