A vizsgabiztos a vizsgaállomáson dolgozik.

Because Hungarian uses the definite article a / az much like English the.

So the sentence has:

• A vizsgabiztos = the examiner
• a vizsgaállomáson = at the test station / examination station

Hungarian normally repeats the article where English would also have the with each definite noun phrase.

A quick note:

• a is used before consonant sounds
• az is used before vowel sounds

So:

• a vizsgabiztos
• az állomás

But in this sentence the article belongs to the whole phrase a vizsgaállomáson, because the word after it is vizsgaállomáson, which begins with a consonant sound.

Yes. Vizsgabiztos is a compound noun.

It is made from:

• vizsga = exam, test
• biztos = commissioner, inspector, official, trusted officer depending on context

Together, vizsgabiztos means the official person who supervises or conducts the exam, often an examiner.

Hungarian forms compounds very freely, much more often than English does. Where English may use two words or a phrase, Hungarian often creates one compound word.

Because the base noun is the compound vizsgaállomás, and then a case ending is added.

Breakdown:

• vizsga = exam, test
• állomás = station
• vizsgaállomás = examination station / testing station
• vizsgaállomáson = at the examination station

So this is: vizsgaállomás + -on

In Hungarian, case endings attach directly to the noun, so the whole thing becomes one word.

The ending -on is a location case ending, specifically the superessive case. It often means on, but in many expressions it is best translated as at or in, depending on idiomatic English.

So:

• vizsgaállomáson = at the examination station

This is very common in Hungarian: the case ending does not always match a single English preposition exactly.

Other examples:

• asztalon = on the table
• egyetemen = at the university
• állomáson = at the station

That is a very common learner question.

Hungarian location endings are not chosen only by literal physical meaning. Many nouns simply prefer a particular case in normal usage.

With állomás (station), Hungarian typically says:

• az állomáson = at the station

not usually:

• az állomásban

Even if English uses in or at, Hungarian may use the superessive ending -on/-en/-ön.

So this is something you often have to learn with the noun:

• iskolában = in school
• irodában = in the office
• állomáson = at the station
• egyetemen = at university

Because Hungarian case endings follow vowel harmony and also some sound-pattern rules.

The superessive has these forms:

• -on
• -en
• -ön
• sometimes -n

Which one appears depends on the noun.

Here the word is:

• vizsgaállomás
• stem used here: vizsgaállomás-
• result: vizsgaállomáson

You do not always have to calculate this from scratch as a beginner; it is often easiest to learn the noun together with its common case forms.

Dolgozik is:

• present tense
• third person singular
• from the verb dolgozik = to work

So it means:

• he/she works
• or more generally works

Hungarian usually does not need a separate subject pronoun like he or she, because the verb ending already shows the person.

That is why dolgozik by itself can mean:

• he works
• she works
• it works
  depending on context.

In this sentence, the noun a vizsgabiztos tells you who is doing the action.

Because dolgozik belongs to the group traditionally called -ik verbs.

In modern everyday Hungarian, this mostly matters in certain conjugated forms, especially in first person singular.

For example:

• dolgozik = he/she works
• dolgozom = I work

So even though the dictionary form ends in -ik, other forms may not keep -ik.

For understanding this sentence, the key point is simply that dolgozik is the normal 3rd person singular form: works.

No, Hungarian word order is relatively flexible. The sentence

• A vizsgabiztos a vizsgaállomáson dolgozik.

is a neutral, natural order meaning roughly:

• The examiner works at the examination station.

But Hungarian can move parts around for emphasis or focus.

For example:

• A vizsgaállomáson dolgozik a vizsgabiztos.
  = It is at the examination station that the examiner works / The examiner works at the examination station.

• Dolgozik a vizsgabiztos a vizsgaállomáson.
  = less neutral, more context-dependent

So the order in your sentence is the standard neutral one, but not the only possible one.

Because the word is a compound:

• vizsga
  • állomás

When Hungarian forms compounds, it usually keeps both parts unchanged, so the vowels meet at the boundary:

• vizsgaállomás

Then the case ending is added:

• vizsgaállomáson

So the double-vowel sequence here is not a special long vowel spelling. It is simply the end of one part plus the beginning of the next part.

A rough pronunciation guide:

• A = short aw
• vizsgabiztos ≈ VIZH-go-bi-stosh
• a vizsgaállomáson ≈ aw VIZH-go-aal-lo-maa-shon
• dolgozik ≈ DOL-go-zik

A few helpful points:

• zs sounds like the s in measure
• sz sounds like English s
• s by itself sounds like English sh
• stress is always on the first syllable of each word in Hungarian

So:

• VIZS-gabiztos
• VIZS-gaállomáson
• DOL-gozik

Yes. Hungarian present tense often covers both the simple present and the present continuous, depending on context.

So:

• A vizsgabiztos a vizsgaállomáson dolgozik.

can mean:

• The examiner works at the examination station.
• The examiner is working at the examination station.

Context tells you whether it is a general fact, a habit, or something happening right now.