minna ha setumei de konransimasita.

みんな means everyone / everybody / all. By itself, it does not specify whether it means all of us, all of you, or all of them. The exact meaning depends on context.

So in a real conversation, みんな could mean:

• everyone
• all the people there
• we all

Japanese often leaves that part to context instead of spelling it out.

は marks the topic of the sentence. So みんなは means something like as for everyone.

This gives the sentence a structure like:

• As for everyone, they got confused because of the explanation.

Using は often suggests that みんな is already known in the conversation, or that the speaker is making a statement about that group.

Yes, みんなが説明で混乱しました is possible, but it sounds slightly different.

Very roughly:

• みんなは = as for everyone
• みんなが = everyone as the grammatical subject, often with more focus on who got confused

So:

• みんなは説明で混乱しました sounds like a general statement about everyone.
• みんなが説明で混乱しました can sound more like it was everyone who got confused.

In many situations, both are possible, but the nuance changes.

Here, で shows the cause / occasion / trigger of the confusion.

So 説明で混乱しました means something like:

• got confused because of the explanation
• was confused by the explanation

Many learners first learn で as meaning:

• at / in a place
• by means of / using

But で can also mark a reason or cause in some cases, especially with events or situations:

• 事故で遅れました = I was late because of an accident
• 病気で休みました = I was absent because of illness

In this sentence, 説明で means the explanation caused the confusion.

Because 説明 is not the direct object of 混乱しました.

The particle を marks the thing directly acted on, but 混乱する here means to become confused / to get confused, so the explanation is not something the speaker is doing confusion to. Instead, it is the cause of the confusion.

That is why で works better here:

• 説明で混乱しました = got confused because of the explanation

If you used を, it would sound like 説明 is the object of the verb, which does not fit well with 混乱する in this meaning.

混乱しました is the polite past form of 混乱する.

Breakdown:

• 混乱 = confusion, disorder
• する = to do
• しました = polite past of する

So 混乱しました literally looks like did confusion, but in natural English it means:

• became confused
• got confused
• was confused

This is a very common Japanese pattern: a noun + する becomes a verb.

Examples:

• 勉強する = to study
• 心配する = to worry
• 混乱する = to become confused / be in confusion

In this sentence, it means they themselves became confused.

With みんな as the subject, みんなは説明で混乱しました means:

• Everyone got confused because of the explanation.

It does not mean:

• Everyone confused the explanation
• Everyone confused someone else

So the subject is the one experiencing the confusion.

Because しました is past polite form, the sentence describes something that already happened:

• 混乱します = get confused / become confused
• 混乱しました = got confused / became confused

Japanese past tense often covers both:

• a completed event in the past
• a past state resulting from something

So depending on context, this could be understood as:

• Everyone got confused or
• Everyone was confused

Yes, it is grammatical and understandable.

However, it sounds a bit formal because of 混乱しました. In everyday speech, people might use more conversational expressions such as:

• みんなは説明で confused? No, that mixes languages and is not natural.
• More natural alternatives:
  • みんなは説明を聞いて混乱しました。
    Everyone got confused after hearing the explanation.
  • みんなはその説明でわからなくなりました。
    Everyone got confused / stopped understanding because of that explanation.
  • みんなは説明を聞いて、頭がこんがらがりました。
    Everyone got mixed up after hearing the explanation.

So the original sentence is fine, especially in written or formal contexts.

Japanese word order is more flexible than English, as long as the particles show each word’s role.

This sentence follows a very common pattern:

• topic + cause + verb

So:

• みんなは = topic
• 説明で = cause
• 混乱しました = verb

You could also say:

• 説明でみんなは混乱しました

That puts more emphasis on 説明で first, something like:

• Because of the explanation, everyone got confused.

So the roles stay clear because of は and で, even if the order changes.

みんな is inherently plural in meaning: it refers to everyone / all the people.

Japanese does not usually mark plural the way English does. There is no need for an ending like -s here. Number is often understood from the word itself or from context.

So:

• みんな already carries the idea of a group
• there is no separate plural ending needed

This is very normal in Japanese.

In some contexts, 説明で could be interpreted in different ways, because で is a flexible particle. But in this sentence, the most natural reading is:

• because of the explanation
• from the explanation
• as a result of the explanation

That is because 混乱しました fits naturally with a cause reading.

If you wanted to make during the explanation clearer, Japanese would often use a different expression, such as:

• 説明中に = during the explanation
• 説明を聞いているときに = while listening to the explanation

So here, learners should understand 説明で mainly as a cause.