Learn Hardcore Russian: Я не понимаю, зачем мы идём туда. - I don’t understand why we are going there.

In Russian, the comma separates the main clause Я не понимаю (“I don’t understand”) from the subordinate clause зачем мы идём туда (“why we’re going there”). This is analogous to English: “I don’t understand, why…” (though in natural English we’d omit the comma). In Russian grammar, subordinate clauses introduced by interrogative words (зачем, почему, как, etc.) are always set off by a comma.

What does зачем mean, and how is it different from почему?

зачем means “for what purpose” or “to what end.” You use it when you’re asking about the goal or reason behind an action.
почему means “why” in the sense of “what causes something.”
Example:

Почему идёт дождь? – “Why is it raining?” (What physical cause?)
Зачем идёт дождь? – “For what purpose is it raining?” (This sounds odd meteorologically, but fits in a poetic or figurative context.)

Why is идём in the present tense instead of some other tense?

In Russian, the present tense идём covers both ongoing actions (“we are going”) and near-future plans (“we’re going to go”). Context tells you if it’s literal movement right now or an upcoming trip. If you wanted to emphasize the future, you could add a time word (e.g., завтра мы идём туда – “tomorrow we’re going there”).

Could you use пойдём instead of идём here?

Yes, you could say Я не понимаю, зачем мы пойдём туда.

идём is the imperfective present (“we go/are going”), focusing on the process.
пойдём is the perfective future (“we will go”), focusing on the completion of the action.
Choosing between them depends on whether you see the action as ongoing or as a one-time event in the future.

What is туда, and how does it differ from сюда or оттуда?

туда is an adverb meaning “to there” (direction away from the speaker).

сюда means “to here” (toward the speaker).
оттуда means “from there.”
These words aren’t cases of nouns but directional adverbs formed from ту (that) + a suffix.

Why is мы placed after зачем, instead of at the very beginning of the subordinate clause?

Word order in Russian is fairly flexible. In the subordinate clause introduced by an interrogative word, that interrogative word (here зачем) usually comes first to signal “question content,” then you follow with subject (мы) and verb (идём). You could say зачем мы идём туда, but not мы зачем идём туда—that would be ungrammatical.

Why is понимаю used here instead of знаю?

понимать means “to understand” (grasp intellectually).
знать means “to know” (have knowledge or facts).
In this sentence you’re expressing a lack of comprehension of the purpose, not a lack of factual information. So не понимаю is the correct choice.

Can you break down the literal English equivalent of each word in Я не понимаю, зачем мы идём туда?

Sure:

Я – “I”
не – “not”
понимаю – “understand”
comma – separates clauses
зачем – “for what purpose/why”
мы – “we”
идём – “go/are going”
туда – “there (to that place)”
Putting it all together word-for-word:
“I not understand for what purpose we go there.”