Customarily, the first bit of advice might be that you use the Monastery's "Search" (top left) to tap the fonts of wisdom here, but your statement of your experience and the form of your question (which amounts to "please answer with a full tutorial") suggested you might consider googling for the knowledge you need.

However, if your experise with mySQL is as you state it, you may find some of the fine Database Programming Tutorials where gmax's contributions (especially the The fine art of database programming) may be helpful.

But as for "a simple way to understand" all that you've asked about... well, the advice in the joke about how to get to Carnegie Hall comes to mind: "Practice, practice, practice!"

Phrased another way, when you've read and understood the documents; studied tutorials; read faqs; and practiced enough, all will become simple, but there are few shortcuts to "understand(ing)" that don't follow sequence