Négy önéletrajz van az asztalon.

In Hungarian, after a number, the noun usually stays singular.

So Hungarian says:

• négy önéletrajz = four CV
• három könyv = three book
• öt ember = five person

This is normal Hungarian grammar. If you use a plural noun without a number, then you do use the plural:

• Önéletrajzok vannak az asztalon. = CVs are on the table.

With exact numbers like kettő, három, négy, Hungarian normally uses singular van in this kind of existential sentence.

So:

• Négy önéletrajz van az asztalon.
• Két alma van a tálban.

This is one of those places where Hungarian does not match English. Even though the meaning is plural, the structure is singular.

If the subject is a regular plural noun without a number, then Hungarian uses vannak:

• Az önéletrajzok az asztalon vannak.

Here van means something like is / exists / there is.

In this sentence, it helps create the meaning there is/there are. Hungarian does not need a separate word like English there in there are four CVs on the table.

So the sentence is built more like:

• Four CVs exist on the table

That sounds strange in English, but it is a good way to understand what Hungarian is doing.

Because Hungarian does not use a dummy subject like English there in existential sentences.

English says:

• There are four CVs on the table.

Hungarian simply says:

• Négy önéletrajz van az asztalon.

So the idea of there are is expressed by the whole structure, especially van, not by a separate word.

It breaks down like this:

• az = the
• asztal = table
• -on = on

So az asztalon literally means on the table.

Hungarian usually uses a case ending instead of a separate preposition. English uses on + the table; Hungarian uses table + on.

Hungarian has two forms of the definite article:

• a before a consonant
• az before a vowel

Since asztal begins with a vowel, you must say:

• az asztal
• az asztalon

Compare:

• a könyv = the book
• az asztal = the table

It works a bit like English a/an in the sense that the form changes before a vowel, but it is the definite article, not the indefinite one.

It is the superessive case, which often means on a surface.

For asztal:

• asztalon = on the table
• asztalra = onto the table
• asztalról = off the table / from the table

So Hungarian makes a clear distinction between:

• being on something
• moving onto something
• moving off something

Hungarian word order is more flexible than English word order. The beginning of the sentence often shows what the speaker is presenting as the topic or main information.

Négy önéletrajz van az asztalon is a very natural neutral sentence. It presents the existence of four CVs on the table.

You could also hear other orders, with slightly different emphasis, for example:

• Az asztalon négy önéletrajz van.
  This puts more attention on the table as the setting.

So the sentence you were given is not the only possible order, but it is perfectly normal.

Yes, that is also possible.

Both of these are natural:

• Négy önéletrajz van az asztalon.
• Az asztalon van négy önéletrajz.

The difference is mainly one of information structure and emphasis, not basic meaning.

Very roughly:

• Négy önéletrajz van az asztalon. = introducing the fact that there are four CVs
• Az asztalon van négy önéletrajz. = starting from the location, on the table

A learner does not need to master all the nuance immediately, but it is good to know that Hungarian word order is flexible.

Yes. In Hungarian, önéletrajz is the standard everyday word for a CV / résumé.

Literally, it is made up of parts meaning something like self-life-writing, so it can look as if it should mean autobiography. But in normal modern usage, it very often means CV/résumé, especially in work or school contexts.

If someone says:

• Küldd el az önéletrajzodat.

that usually means:

• Send your CV.

not Write your life story.

A rough guide:

• négy: the é is a long vowel, and gy is a soft consonant, somewhat like a dy sound.
• önéletrajz:
  
  • ö is a rounded front vowel, not exactly like anything in standard English
  • é is long
  • j is pronounced like English y

A rough English-friendly approximation might be:

• négy ≈ naidge with a very soft ending
• önéletrajz ≈ uh-nay-leh-tryz

But those are only approximations. The main things to notice are:

• Hungarian spelling is quite regular
• accents matter
• ö / ő are different vowels from o / ó

They are important parts of the spelling, not optional marks.

In this sentence:

• é is a long vowel
• ö is a different vowel from o
• gy is a single consonant sound in Hungarian spelling

So:

• negy would not be the same as négy
• oneletrajz would not be the same as önéletrajz

In Hungarian, vowel length and vowel quality can change the word, so you should try to learn the accents as part of the word itself.