Learn Hardcore Indonesian: Pada festival itu, banyak sukarelawan membantu mengatur lomba untuk anak-anak. - At that festival, many volunteers help organize competitions for children.

di is mostly at / in / on for physical locations:
- di rumah – at home
- di Jakarta – in Jakarta
pada is often used with:
- time expressions: pada hari Senin (on Monday), pada tahun 2020
- events / occasions / situations: pada festival itu, pada rapat kemarin (at yesterday’s meeting)
- sometimes for abstract objects: pada kesempatan ini (on this occasion)

In everyday speech, you might also hear di festival itu. It’s not wrong, but pada festival itu sounds a bit more formal and “bookish” and fits well in written Indonesian.

Why is it festival itu and not itu festival?

In Indonesian, demonstratives like ini (this) and itu (that) usually come after the noun:

buku ini – this book
buku itu – that book
festival itu – that festival

Itu festival can appear, but it has a different feel: it’s more like “that is a festival” or “that festival (you’re talking about)” depending on context and intonation.

For a simple noun phrase that festival, the normal order is festival itu.

How do we know this sentence is in the past if there is no past tense marking?

Indonesian verbs do not change form for tense (past / present / future).

Time is usually shown by:

time words: kemarin (yesterday), tadi (earlier), besok (tomorrow), nanti (later)
context, including words like itu that can refer to a specific event already known or completed

In pada festival itu, itu suggests a specific festival already known in the conversation or text, and often this implies the event is in the past. But grammatically, the sentence could also be talking about a current or even future festival, depending on context.

So the verb forms membantu and mengatur themselves do not show tense.

What does banyak do here, and do I need to make sukarelawan plural?

Banyak means many / a lot of.

In Indonesian:

Nouns usually don’t change form for plural.
Plurality is shown by words like banyak (many), beberapa (several), para (for groups of people), or by context.

So:

sukarelawan – volunteer / volunteers
banyak sukarelawan – many volunteers

You do not add any plural ending. Banyak already tells you it’s more than one.

Is there any difference between banyak sukarelawan and banyaknya sukarelawan?

Yes.

banyak sukarelawan – a neutral phrase meaning many volunteers.
banyaknya sukarelawan – more like the number of volunteers or how many volunteers (there were), often with an emotional or descriptive nuance.

Examples:

Pada festival itu, banyak sukarelawan membantu.
At that festival, many volunteers helped.
Banyaknya sukarelawan membuat acara berjalan lancar.
The (large) number of volunteers made the event run smoothly.

In your sentence, banyak sukarelawan is the correct, simple way to say many volunteers.

What does sukarelawan literally mean?

Sukarelawan means volunteer.

It comes from:

suka rela – willing, doing something voluntarily
-wan – a suffix often used for people (like wartawan – journalist)

So sukarelawan is basically a person who does something willingly / voluntarily → a volunteer.

Why do we have two verbs together: membantu mengatur? Is that normal?

Yes, it’s very normal. Indonesian often uses Verb 1 + Verb 2 without to:

membantu mengatur – help (to) organize
mulai belajar – start (to) study
ingin makan – want to eat

So banyak sukarelawan membantu mengatur lomba is like many volunteers helped (to) organize the competition(s).

You don’t need a word like to between the verbs.

Can I say membantu untuk mengatur instead of membantu mengatur?

You can, and you will see it:

membantu untuk mengatur lomba

However:

In many cases, untuk is unnecessary and sounds more formal or wordy.
Learners are usually safer keeping it simple:
membantu mengatur lomba is very natural and correct.

So membantu mengatur is the preferred, more concise form here.

What’s the difference between bantu and membantu, atur and mengatur?

Bantu and atur are root verbs:

bantu – help
atur – arrange, set, organize

Adding the prefix meN- (which changes shape depending on the first letter) gives:

membantu (meN- + bantu)
mengatur (meN- + atur)

Very roughly:

The meN- form is the standard, active verb form in neutral/formal Indonesian.
The bare root (bantu, atur) appears:
- as a dictionary form
- in commands: Bantu saya! (Help me!)
- in noun/compound forms: pengatur acara (event organizer), aturan (rule)

In your sentence, membantu and mengatur are the appropriate active-verb forms.

What does lomba mean here? Is it singular or plural?

Lomba means contest / competition.

It can be:

a competition
the competition
competitions (in general)

Indonesian doesn’t mark singular/plural with endings or articles. Context decides:

With mengatur lomba untuk anak-anak, in natural English we’d often say organize competitions for children, because festivals usually have several events. But grammatically, lomba itself is just neutral: it doesn’t say one or many.

Why is anak-anak repeated? Does it always mean plural?

Reduplication (repeating a word) is one common way to show plurality in Indonesian.

anak – child
anak-anak – children

So untuk anak-anak = for children.

Notes:

Sometimes a single anak can also mean child / children in a general sense, like anak SD (elementary-school kid(s)), depending on context.
But anak-anak clearly signals more than one child or the category children.

What does untuk do in lomba untuk anak-anak, and how is it different from bagi or kepada?

Untuk here means for:

lomba untuk anak-anak – competitions for children

Very roughly:

untuk – for (purpose, target, intended audience)
- kado untuk ibu – a gift for mom
bagi – also “for”, but more formal or written, often interchangeable with untuk:
- lomba bagi anak-anak – more formal than lomba untuk anak-anak
kepada – to, used for giving or addressing someone:
- berikan hadiah kepada anak-anak – give the prize to the children

In your sentence, untuk is the most natural and common choice.

Can I change the word order, like Banyak sukarelawan pada festival itu membantu mengatur lomba untuk anak-anak?

Yes, Indonesian word order is somewhat flexible, though some orders sound more natural.

Your original:

Pada festival itu, banyak sukarelawan membantu mengatur lomba untuk anak-anak.
Emphasis starts with the event/time: At that festival, many volunteers…

You can also say:

Banyak sukarelawan membantu mengatur lomba untuk anak-anak pada festival itu.
Now the focus starts on many volunteers, and pada festival itu comes later.

Both are grammatically fine.
The original version is a very natural way to set the scene in writing: Pada festival itu, …