Trying to Figure out Fermenting

I was derping around the internet the other day, and I became interested in fermenting because I was looking for a kimchi recipe. I was going to tell you all about the things I learned, when I found this article refuting most of what I'd just found out. 

Ugh, how annoying. But I’m also confused. From every site I've looked at I’ve found that fermenting seems really complicated, but last summer I made Kimchi without consulting any of them. I just put some cabbage in salt water, then added spices and crammed them all in a jar, then put it in the fridge. I don’t know if the jar was air sealed. It certainly wasn’t sterilized. Some people talk about having to leave the kimchi out for a while and that putting it in the fridge stops the fermenting, but that’s what I did, and to my knowledge it did ferment. It got sour like the recipe said and I didn’t get sick. There are also some people who complain about the cabbage getting slimy and having to skim the foam off the top every few days. Again, I didn’t even know this was a problem. I guess I’m just lucky when it comes to cooking.