basics 1 nuances
The explanation in the tips and notes of topics and subjects makes absolutely no sense to me as an english speaker and I hope it is resolved to make more sense for people that are not linguistic experts. I wish there were more examples or explanations that actually translate to make sense in English. Bread, for one, is food??? What does that mean? Just say bread is food. What is the difference between the general subject and general topic?
Oh boy, topic particles are one of those things that are really hard to translate or explain.
Just as a disclaimer, I'm much, much more familiar with how the topic particle works in Japanese, and while there seems to be lots of overlap I could be wrong on some details in the context of Korean.
Basically, Korean, as I understand it, is a pro-drop language, meaning you can drop certain words if it's clear from context. The topic is very often dropped. For example, if the topic of conversation is apples, you can just say "are tasty" because the listener knows that it's the topic, and can therefore infer from context. In this case, the topic particle is used to either introduce a new topic (like, "ok, now we're gonna talk about this, so things I say will now refer to this") or if you need to clear up ambiguity (like, "remember, we're talking about this, and I'm not dropping it because otherwise it might be confusing, but it's still the topic").
It's also used a lot for contrast. For example, "these things are not good, but this thing that I'm emphasizing by using the topic particle is good." This is why I find it often helpful to translate the topic particle as "as for this thing." (It's also why when you're complimenting someone on their eyes or something you should use the subject particle because the topic particle holds the notion of contrast, so you may be unintentionally implying that their other features aren't good).
The topic particle also has a feeling of exclusivity. Like, "regardless of anything else, this thing is good." You're talking about this thing, not anything else.
Also, the topic particle isn't used in some questions. If you ask, "what is it?" or "who does this?" you would use the subject particle on "what" and "who" because you can't make something the topic if it's indefinite. However, you could use it if you phrased it like "this thing (topic), what is it?" or "the person that does this (topic), who is it?"
I'm probably not explaining it too well, but I hope this helps!
On the contrary you explained well enough. It is indeed not something you can translate directly, sometimes not even indirectly. When learning a language from the other side of the world, people need to be a bit more humble in their approach and go in knowing nothing is what you expect. In fact, like Korean and Japanese, it's literally the opposite.