zhìyuànzhě zài juānzèngdiǎn bāngzhù dàjiā.

在 marks the location where the action happens. In this sentence, 在捐赠点 means at the donation site / at the donation station.

A very common Mandarin pattern is:

Subject + 在 + place + verb + object

So:

志愿者 在 捐赠点 帮助 大家。
= Volunteers help everyone at the donation site.

Unlike English, Mandarin often puts the location before the main verb.

志愿者 means volunteer.

It can be broken down like this:

• 志愿 = voluntary, willing, volunteering
• 者 = a person who does something

So 志愿者 literally means a person who volunteers.

In this sentence, 志愿者 can be understood as:

• the volunteer if the context is singular, or
• volunteers in a general sense

Mandarin nouns usually do not show singular/plural automatically, so context tells you which is meant.

Mandarin does not have articles like the, a, or an.

So:

• 志愿者 can mean a volunteer, the volunteer, or volunteers
• 捐赠点 can mean a donation site or the donation site

The exact meaning depends on context.

This is very normal in Chinese. Learners often want to insert an article mentally, but Mandarin usually leaves that information unstated unless it is important.

捐赠点 means donation site, donation point, or collection point.

It is made of:

• 捐赠 = donate; donation
• 点 = point, spot, site

Here, 点 does not mean the time word o’clock. It means a location or designated spot.

So 捐赠点 is a place where people go to donate something.

That is a good question because the literal parts can be misleading.

• 大 = big
• 家 = family, home, household

But together, 大家 is a fixed expression meaning everyone or all the people here.

It does not usually mean big family in modern everyday use. In this sentence, 帮助大家 means help everyone.

Mandarin commonly places time and location before the main verb.

So the natural order is often:

Subject + time + place + verb + object

In this sentence:

• 志愿者 = subject
• 在捐赠点 = location
• 帮助 = verb
• 大家 = object

English often says:

• Volunteers help everyone at the donation site

Mandarin prefers:

• Volunteers at the donation site help everyone

Not because the meaning is different, but because Chinese grammar usually introduces the setting before the action.

Usually, that sounds unnatural.

The normal choice is:

志愿者在捐赠点帮助大家。

The location phrase 在捐赠点 usually comes before the verb 帮助.

If you put 在捐赠点 at the end, it may sound awkward because Mandarin generally prefers the location to appear before the action it describes.

So for learners, the safest pattern is:

Subject + 在 + place + verb + object

Here it is a verb, meaning to help.

So:

• 帮助大家 = help everyone

In Mandarin, 帮助 can also be a noun in other sentences, meaning help or assistance.

For example:

• 谢谢你的帮助。 = Thanks for your help.

But in your sentence, it is clearly the main verb.

No. In Mandarin, 帮助 can directly take an object.

So:

• 帮助大家 = help everyone

You do not need a word corresponding to English to here.

English says:

• help everyone

Mandarin works the same way in this case:

• 帮助大家

Not always, but it is very common and natural.

大家 usually refers to everyone in the relevant group—the people present, the people being talked to, or people in a shared situation.

Other words can also mean everyone/all people, depending on context, such as:

• 每个人 = every person / everyone
• 所有人 = all people / everyone

Compared with those:

• 大家 often sounds more natural and conversational
• 每个人 emphasizes each individual person
• 所有人 emphasizes the whole group

In this sentence, 大家 is a very natural choice.

It is pronounced:

zhì yuàn zhě

The tones are:

• 志 zhì — 4th tone
• 愿 yuàn — 4th tone
• 者 zhě — 3rd tone

A few pronunciation notes:

• zh is not the same as English j. It is a retroflex sound.
• ü is not written in yuàn, because after y, standard pinyin drops the dots. So yuàn is pronounced with the ü-type vowel, not like English you.
• zhě has a 3rd tone, which is often pronounced lower and shorter in normal speech unless stressed.

Mandarin nouns usually do not change form for plural.

So 志愿者 can mean:

• a volunteer
• the volunteer
• volunteers

Context tells you which meaning is intended.

Sometimes Mandarin does use plural marking, especially with pronouns or certain human nouns, such as 们, but it is not required here. In fact, saying 志愿者们 is possible, but it adds emphasis to the group of volunteers. The simple 志愿者 is perfectly normal.

In practice, it mainly tells you where the helping happens.

So the most natural understanding is:

The volunteers help everyone at the donation site.

Chinese location phrases before the verb often describe the setting of the action. In many situations, that also indirectly tells you where the subject is, but grammatically the key idea is the location of the action 帮助.

So it is best to understand 在捐赠点 as the place where the helping takes place.