Best ways to learn ACTUAL information about kitchener essences?

I've been in the sub for a while now but I still feel confused about how to actually see and understand the essences, and I get told there's resources on this sub but idk if I'm looking up the wrong things or just can't find them or what. So I was wondering if anyone knew the best threads on here to read to learn, or any explanations? I don't want to go off anything else like googling it really because there seems to be a butt ton of misinformation and it's only going to confuse me further.

So yeah any tips/ places to read or learn about how to identify, apply the essences, tell if it's harmonious, and what they actually mean?