Learn Hardcore Finnish: Kun menee virastoon, ottaa vuoronumeron automaatista. - When you go to an office, you take a queue number from the machine.

Finnish often uses the zero person (an “implicit subject”) to express a general instruction or what people typically do.
So Kun menee virastoon, ottaa vuoronumeron automaatista is like “When (someone/you) go(es) to the office, (you) take a queue number from the machine.”
It’s common in instructions, rules, and general statements.

Why are the verbs menee and ottaa in 3rd person singular, not menet / otat?

Because of the zero person construction: the verb is in 3rd person singular even though the meaning can be “you/one/people”.
If you want to address someone directly, you can say:

Kun menet virastoon, otat vuoronumeron automaatista. (direct you)

What’s the difference between kun and jos here?

kun usually means “when” in the sense of a typical/expected situation: “when you go (as you do), then you take…”.
jos is more conditional: “if you happen to go…, then…”.
Both can be possible depending on context, but kun fits general routine instructions very well.

Why is there a comma: Kun menee virastoon, ...?

In Finnish, a subordinate clause starting with kun is typically separated from the main clause with a comma:

Kun + clause, main clause.
So Kun menee virastoon, ottaa... follows standard punctuation.

What case is virastoon, and why that ending?

virastoon is illative (“into/to inside”), expressing movement into a place:

virasto = an office (often a public office/agency)
virastoon = “(in)to the office”

It answers “where to?” (minne?).

What case is automaatista, and why not something like automaattiin?

automaatista is elative (“out of/from inside”), showing the source you take something from:

automaatti = machine/vending machine/automaton
automaatista = “from (inside) the machine”

Because you take the ticket out of the machine, -sta/-stä fits.

Why is it vuoronumeron and not vuoronumeroa?

vuoronumeron is the total object (often marked with -n in the singular), implying you take one complete item (a whole queue ticket/number).
vuoronumeroa (partitive) would suggest an incomplete/ongoing action or an indefinite amount, which doesn’t fit as well here.

Is vuoronumero one word, and what does it literally mean?

Yes, it’s a compound:

vuoro = turn (as in your turn)
numero = number
So vuoronumero is literally “turn number”, i.e., a queue number.

Could this be written using the passive instead?

Yes. Finnish often uses the passive for general instructions too, for example:

Kun mennään virastoon, otetaan vuoronumero automaatista.
This sounds a bit more like “we/people do this” (still general), and it’s very common in spoken Finnish and signage/instructions.

Does the present tense here mean “right now”, or “in general”?

Here it’s the general present: it describes a habitual/typical procedure, not necessarily something happening at this exact moment.
Finnish present tense commonly covers “in general / whenever this happens” meanings, especially with kun-clauses and instructions.