mousikomisyo no kakikata ga wakaranai node, kakariin ni kikimasita.

書き方 means how to write or the way of writing.

It is formed from:

• 書く = to write
• 方（かた） = way of doing something

So:

• 書き方 = way of writing / how to write
• similarly:
  • 食べ方 = how to eat
  • 使い方 = how to use
  • 読み方 = how to read

In this sentence, 申込書の書き方 means how to fill out / write an application form.

The の connects 申込書 and 書き方.

• 申込書 = application form
• 書き方 = way of writing

So 申込書の書き方 literally means the application form's way of writing, which sounds unnatural in English, but in natural English it means:

• how to write an application form
• how to fill out an application form

This is a very common use of の to connect two nouns.

In 書き方が分からない, the thing that is not understood is marked by が.

• 書き方が分からない = I don't understand the way to write it / I don't know how to fill it out

With 分かる, the thing understood is often marked with が:

• 日本語が分かる = I understand Japanese
• 意味が分からない = I don't understand the meaning

English learners often expect を, but with 分かる, が is very common.

This is an important distinction.

• 知らない = do not know (a fact, a person, a piece of information)
• 分からない = do not understand / do not know how / it is unclear to me

Here the speaker is talking about how to write the form, so it is about understanding a method or procedure. That is why 分からない is the natural choice.

Compare:

• 彼を知らない = I don't know him.
• 答えを知らない = I don't know the answer.
• やり方が分からない = I don't know how to do it.

Both ので and から can mean because, but they have a slightly different feel.

• ので sounds softer, more explanatory, and a bit more polite
• から can sound more direct or more like the speaker's personal reasoning

So:

• 分からないので、係員に聞きました。 = Because I didn't know, I asked a staff member.

This sounds natural and polite, especially in practical situations like forms, offices, stations, or stores.

係員（かかりいん） means staff member, attendant, or clerk, depending on context.

It refers to a person in charge at a counter, office, station, event, or similar place.

Examples:

• at a station: station staff
• at a reception desk: clerk or attendant
• at an event: staff member

It is a useful general word when you do not know the person's exact job title.

With 聞く meaning to ask, the person you ask is marked by に.

• 先生に聞く = ask the teacher
• 友達に聞く = ask a friend
• 係員に聞きました = asked a staff member

Be careful: 聞く can also mean to hear or to listen depending on context, but here it clearly means to ask.

Yes, 聞く can mean several related things:

• to hear
• to listen
• to ask

The meaning depends on context.

In this sentence:

• 係員に聞きました

because there is a person marked by に, the meaning is asked a staff member.

Some examples:

• 音楽を聞く = listen to music
• 話を聞く = listen to a story / hear what someone says
• 先生に聞く = ask the teacher

The main action of the sentence is 聞きました (asked), so the whole sentence is anchored in the past.

The first part, 書き方が分からないので, describes the reason at that time:

• Because I didn't know how to fill it out, I asked a staff member.

Japanese often does not shift every part into past tense the same way English does. A non-past form inside a reason clause can still describe the situation that existed at that time.

You may also hear:

• 書き方が分からなかったので、係員に聞きました。

This is also natural and makes the past situation more explicit.

Yes, the subject is omitted, which is very common in Japanese.

From context, we understand that the same person is both:

• the one who did not know how to fill out the form
• the one who asked the staff member

So in English, we would naturally supply I:

• I didn't know how to fill out the application form, so I asked a staff member.

Japanese often leaves out subjects when they are clear from context.

Japanese usually puts background information, conditions, reasons, and context before the main statement.

So the structure is:

• [reason] + ので + [main action]

Here:

• 申込書の書き方が分からないので = because I didn't know how to fill out the application form
• 係員に聞きました = I asked a staff member

This order is very normal in Japanese.

Yes, and in many contexts that is the most natural English translation.

Even though 書く literally means to write, with forms and documents 書き方 often means:

• how to fill out
• how to complete
• how to write in the required way

So 申込書の書き方 is often best understood as:

• how to fill out the application form

rather than the more literal but less natural:

• how to write the application form

Yes. It is polite because it ends with 聞きました, which is in the ます-form past tense.

• 聞く = plain dictionary form
• 聞きます = polite non-past
• 聞きました = polite past

Also, ので gives the sentence a somewhat softer and more polite tone than から often would.

So this is a natural polite sentence for everyday use.