Selama libur sekolah, kami akan berlibur ke pulau kecil itu.

Selama means during or throughout. It introduces a time period in which something happens.

So Selama libur sekolah means during the school holiday.

Putting it at the beginning is very natural in Indonesian when you want to set the time first. You could also move it later:

Kami akan berlibur ke pulau kecil itu selama libur sekolah.

That means the same thing, but the original sentence gives a little more emphasis to the time frame.

Libur sekolah means school holiday or school break.

• libur = a holiday, day off, break
• sekolah = school

Together, they mean the period when school is not in session.

A native English speaker may expect something like the school holiday, but Indonesian often does not use articles like the or a the way English does.

This is a very important Indonesian distinction.

Both kami and kita can mean we, but:

• kami = we, but not including the person being spoken to
• kita = we, including the person being spoken to

So in this sentence, kami tells you that the speaker and their group will go on vacation, but the listener is not part of that group.

Akan is a future marker. It often corresponds to will in English.

So:

• kami berlibur = we vacation / we are on vacation
• kami akan berlibur = we will go on vacation

In Indonesian, future meaning can sometimes be understood from context even without akan, but adding akan makes the future meaning clearer and more explicit.

They are related, but they are doing different jobs.

• libur in libur sekolah is a noun-like expression meaning holiday/break
• berlibur is a verb meaning to go on vacation or to spend a holiday

The prefix ber- often forms verbs connected with having, doing, or engaging in something.

So:

• libur sekolah = the school holiday
• berlibur = to vacation / to go on holiday

Even though they come from the same root, they are not repetitive in a bad way. This is perfectly natural Indonesian.

Ke is a preposition meaning to when talking about movement toward a place.

Since the sentence is about going on vacation to an island, Indonesian uses ke:

berlibur ke pulau kecil itu = go on vacation to that small island

Compare:

• di = at/in/on a place
• ke = to a place
• dari = from a place

So if they were already there, you might say:

Kami berlibur di pulau kecil itu.
= We are vacationing on that small island.

Indonesian word order is different from English.

The usual order is:

noun + adjective + demonstrative

So:

• pulau = island
• kecil = small
• itu = that

Together:

pulau kecil itu = that small island

In English, we say that small island. In Indonesian, the noun usually comes first.

More examples:

• rumah besar itu = that big house
• buku baru ini = this new book

Literally, itu means that. But in real Indonesian, itu can also make something sound definite, a bit like the in English, depending on context.

So pulau kecil itu could be understood as:

• that small island
• or sometimes the small island, if both speaker and listener already know which island is meant

Its position at the end is normal in Indonesian noun phrases:

noun + adjective + itu/ini

Examples:

• mobil merah itu = that red car
• orang tua itu = that old person / that parent, depending on context

Yes, you may hear both, but they are not always used in exactly the same way.

• libur sekolah is very common for school break / time off from school
• liburan sekolah is also common and often feels a bit more like school vacation/holiday period

In many everyday situations, they are close in meaning. In this sentence, selama libur sekolah sounds very natural.

Also note:

• libur often refers to the break itself
• liburan can refer more to the vacation period or the activity of vacationing

But in casual speech, the lines can blur.

The comma is natural because Selama libur sekolah is an introductory time phrase.

It helps show a pause:

Selama libur sekolah, kami akan berlibur ke pulau kecil itu.

In informal writing, people may sometimes leave the comma out, but using it here is good and clear punctuation.

Yes, Indonesian word order is fairly flexible, especially with time expressions.

For example, these are all natural:

Selama libur sekolah, kami akan berlibur ke pulau kecil itu.
Kami akan berlibur ke pulau kecil itu selama libur sekolah.

The basic meaning stays the same. The difference is mainly emphasis:

• starting with Selama libur sekolah emphasizes when
• starting with Kami emphasizes who

If you say:

Selama libur sekolah, kami berlibur ke pulau kecil itu.

it could still be understood, but it depends more on context. It might sound like:

• a habitual action: During school holidays, we vacation on that small island
• or a planned/future action, if the situation already makes that clear

Using akan removes that ambiguity and clearly points to the future.

Berlibur is natural and correct. It is a good standard word for to go on vacation.

But in everyday speech, people might also say things like:

• pergi liburan = go on vacation
• liburan ke ... = vacation/go on holiday to ...
• jalan-jalan ke ... = go sightseeing/travel around to ...

So berlibur is not the only option, but it is a very normal and grammatically neat choice in this sentence.