Početak radova je nakon odobrenja i predujma.

The base word is radovi or rad.

In this sentence, radova is the genitive plural form, and it depends on početak:

• početak = beginning, start
• radovi = works, jobs, construction works
• početak radova = the start of the works / the beginning of the work

Croatian often uses the genitive after nouns like početak to show "the beginning of what?"

Compare:

• početak sastanka = the start of the meeting
• početak dana = the start of the day
• početak radova = the start of the works

So radova is there because početak normally takes a genitive complement.

In Croatian, radovi is very commonly used in business, technical, and construction contexts to mean works, operations, or jobs being carried out.

So:

• rad = work in a general sense
• radovi = works / jobs / construction works / project works

That means:

• početak rada usually sounds more like the start of work in a general or abstract sense
• početak radova sounds more like the start of the actual works/projects/tasks, especially in formal or professional language

In this sentence, radova is probably being used in that practical, project-related sense.

Because they follow nakon, and nakon requires the genitive case.

So:

• odobrenje → odobrenja
• predujam → predujma

This is a very common pattern:

• nakon sastanka = after the meeting
• nakon ručka = after lunch
• nakon odobrenja = after approval
• nakon predujma = after the advance payment

So the structure is:

• nakon + genitive

Predujam means advance payment, down payment, or sometimes deposit, depending on context.

It refers to money paid before the work or service is fully completed.

In business contexts:

• predujam = an amount paid in advance
• plaćanje predujma = payment of an advance
• nakon odobrenja i predujma = after approval and the advance payment

A very close English translation here would often be after approval and advance payment.

Odobrenje means approval or authorization.

In this sentence, it probably refers to some required approval before work can start, for example:

• management approval
• permit approval
• client approval
• administrative authorization

So nakon odobrenja means after approval has been given.

This sentence uses a noun-based, formal style, which is common in business and administrative Croatian.

Instead of saying:

• Radovi počinju nakon odobrenja i predujma. = The works begin after approval and advance payment.

it says:

• Početak radova je nakon odobrenja i predujma. = The start of the works is after approval and advance payment.

This sounds more formal, contractual, or administrative.

So je is simply the verb is, linking:

• Početak radova = subject
• nakon odobrenja i predujma = predicate expression

It is understandable and natural enough, but it sounds formal and a bit administrative/business-like.

You might see it in:

• contracts
• offers
• invoices
• project documentation
• emails to clients

In everyday speech, people might more often say something like:

• Radovi počinju nakon odobrenja i predujma.
• S radovima krećemo nakon odobrenja i predujma.

Those feel more verbal and conversational.

Croatian does not have articles like English a/an and the.

So nouns appear without articles, and definiteness is understood from context.

For example:

• početak can mean a start or the start
• predujam can mean an advance payment or the advance payment
• odobrenje can mean approval or the approval

In this sentence, English usually needs articles, but Croatian does not.

Literally, nakon means after, so it expresses sequence in time.

But in a sentence like this, it also carries a practical condition-like meaning:

• first approval and advance payment happen
• then the work starts

So although the word itself means after, the overall message is often understood as:

• the work starts only once approval and advance payment have been received

That is why this kind of phrasing is common in contracts and project communication.

Yes, Croatian word order is fairly flexible, but not all orders sound equally natural.

The given sentence:

• Početak radova je nakon odobrenja i predujma.

is clear and neutral in a formal context.

You could also say:

• Nakon odobrenja i predujma počinju radovi.
• Radovi počinju nakon odobrenja i predujma.

These alternatives are often more natural in ordinary usage.

A different word order is possible, but the original version is especially suited to formal written language.

Yes. i means and, so it joins two prerequisites:

• odobrenja = approval
• predujma = advance payment

So the sentence means that the start of the works comes after both:

1. approval
2. advance payment

If only one were required, the sentence would be phrased differently.