kaigi no mae ni, siryou wo tukue no ue ni narabete okimasu.

～ておく adds the idea of doing something in advance or as preparation.

So:

• 並べます = arrange / line up
• 並べておきます = arrange beforehand, so it will be ready

In this sentence, that nuance matters because the action is being done before the meeting.

They do two different jobs:

• 会議の前に: に marks a time point
  → before the meeting
• 机の上に: に marks the place where something is put/ends up
  → onto/on the desk

So even though the same particle appears twice, the meaning depends on what comes before it.

Here, の connects nouns.

• 会議の前 = the front/before of the meeting → before the meeting
• 机の上 = the top of the desk → on the desk

This pattern is very common:

• A の 前 = before/in front of A
• A の 上 = on top of A
• A の 下 = under A
• A の 中 = inside A

Because the particles mark different roles:

• 資料を: を marks the direct object
  → the thing being arranged
• 机の上に: に marks the destination/location
  → where the materials are being arranged

So the structure is basically:

[thing being arranged] を [place where it will be arranged] に 並べる

Yes, the subject is omitted.

Japanese often leaves out the subject when it is clear from context. Depending on the situation, this could mean:

• I will arrange them
• we will arrange them
• someone will arrange them

In a normal conversation, the listener usually understands who is responsible without the subject being stated.

In 並べておきます, the おく is an auxiliary expression attached to the て-form.

When おく is used this way, it is very often written in hiragana:

• 並べておきます

If it is the full verb meaning to put/place, kanji is more common:

• 本を机に置きます

So the hiragana spelling helps show that this is the grammar pattern ～ておく, not the main verb 置く in its literal sense.

並べる is an ichidan verb and it is transitive.

That means it takes a direct object:

• 資料を並べる = arrange the materials

Compare it with the intransitive verb:

• 並ぶ = to line up / to be lined up

So:

• 本が並ぶ = the books are lined up
• 本を並べる = arrange the books

This transitive/intransitive pair is very common in Japanese.

Because this phrase is talking about time, not the place where an action happens.

• に can mark a time point
• で usually marks the place where an action occurs

So:

• 会議の前に = before the meeting
• 会議の前で would sound like in front of the meeting in a physical-location sense, which does not fit here

Yes, Japanese word order is fairly flexible because the particles show each word’s role.

For example, these are possible:

• 会議の前に、資料を机の上に並べておきます。
• 資料を机の上に、会議の前に並べておきます。
• 会議の前に資料を机の上に並べておきます。

That said, the original order is natural because it presents:

1. when
2. what
3. where
4. action

So it is a very clear and standard way to say it.

This is a very common question.

• 机の上に並べる focuses on where the materials are placed
• 机の上で並べる focuses more on where the action of arranging happens

With verbs like 置く, 並べる, 入れる, Japanese often uses に because the result is important: the materials end up on the desk.

So here, 机の上に is the natural choice.

It can mean either. Japanese nouns usually do not show singular/plural clearly unless the context makes it obvious.

So 資料 could mean:

• a document
• documents
• materials
• handouts

In this sentence, it will usually be understood from the situation.

Yes, but the nuance changes.

• 並べておきます = someone will arrange them beforehand
• 並べてあります = they have been arranged and are in that prepared state

So:

• 会議の前に、資料を机の上に並べておきます。
  focuses on the preparatory action
• 資料が机の上に並べてあります。
  focuses on the resulting state

In other words, ～ておく is about doing it in advance, while ～てある is about it being left ready.