@learninglearning Those are sometimes called the “こそあど words”, because the variations start with those syllables:
ここ - a location close® to the speaker, therefore "here"
そこ - a location close® to the listener, therefore "there"
あこ - a location away from both the speaker and the listener, something like "over there"
どこ - to ask a question, therefore “where”
The same principle is used with words for several grammatical functions, for example
これ - something close® to the speaker, therefore "this"
それ - something close® to the listener, therefore "that"
あれ - something away from both the speaker and the listener, something like "that over there"
どれ - to ask a question, therefore “which (of those)”
こう - something like "in this way"
そう - something like "in that way"
ああ (instead of あう) - something like "in some other way"
どう - something like “in what way” or “how”
I haven’t reached them in this course, but I honestly have no good idea how to express the different concepts in one word each. In English, there’s the distinction between “this” and “that” that follows a similar concept. In German, one probably has to work with brackets extensively, like “das (näher bei mir)”, “das (näher bei Dir)” or something like that.