haengsa jeone annaemuneul jasehi ilgeo boseyo.

전에 means before.

In this sentence, it comes after the noun 행사 (event) to make the phrase 행사 전에, meaning before the event.

A very common pattern is:

noun + 전에 = before the noun

• 수업 전에 = before class
• 식사 전에 = before the meal
• 시험 전에 = before the exam

It can also be used after a verb-based form:

• 읽기 전에 = before reading
• 가기 전에 = before going

So here, 행사 전에 sets the time background for the rest of the sentence.

Because 전에 itself is doing the job of attaching to 행사.

In Korean, expressions of time often do not need an extra particle before words like 전에 or 후에. So:

• 행사 전에 is natural
• 행사 전에는 is also possible, but it adds topic/contrast emphasis

For example:

• 행사 전에 읽어 보세요. = neutral
• 행사 전에는 꼭 읽어 보세요. = as for before the event / at least before the event, please definitely read it

So the version in your sentence is the plain, natural one.

을 is the object marker.

It marks 안내문 as the thing being read. In other words, it tells you what the action is happening to.

Pattern:

• noun + 을/를 = the object of the verb

Examples:

• 책을 읽다 = to read a book
• 물을 마시다 = to drink water
• 안내문을 읽다 = to read the notice/information sheet

Since 안내문 ends in a consonant, it takes 을, not 를.

안내문 is a noun meaning something like an information notice, instruction sheet, announcement text, or guidance document, depending on context.

It is made from:

• 안내 = guidance, information
• 문 = writing/text/document

So 안내문 is written information given to people so they know what to do or what to expect.

In real life, it could be:

• a printed notice
• event instructions
• a handout
• a sign or announcement text

자세히 is an adverb, meaning carefully, in detail, or thoroughly.

It comes from the adjective 자세하다 (to be detailed).
To turn many Korean descriptive words into adverbs, Korean often uses -히.

So:

• 자세하다 = to be detailed
• 자세히 = in detail / carefully

In this sentence, 자세히 describes how you should read the notice.

Compare:

• 읽어 보세요. = please read it / try reading it
• 자세히 읽어 보세요. = please read it carefully / in detail

This is a very common learner question.

읽으세요 is a direct polite request:

• Please read it.

읽어 보세요 uses the grammar -아/어 보다, which literally comes from to see, but grammatically means:

• try doing
• do it and see
• sometimes take a look

So 읽어 보세요 sounds a little softer and more natural in many instruction contexts. It often suggests:

• please try reading it
• please take a look at it
• please read through it

In practical usage, it can feel less blunt than 읽으세요.

The grammar is:

verb stem + 아/어 보다

It means to try doing something.

Here:

• dictionary form: 읽다
• stem: 읽-
• connect with -어: 읽어
• plus 보다: 읽어 보다
• polite request: 읽어 보세요

More examples:

• 먹어 보다 = try eating
• 써 보다 = try writing / try using
• 입어 보다 = try wearing on
• 가 보다 = try going / go and see

In this sentence, it does not necessarily mean an experimental try in the strongest sense. Very often it just softens the instruction and makes it sound more natural.

Because when a verb is followed by -아/어 보다, it uses the -아/어 connective form, not the -(으)세요 form directly.

So the steps are:

1. Start with 읽다
2. Make the -어 form: 읽어
3. Add 보다 → 읽어 보다
4. Make it polite: 읽어 보세요

That is why you get 읽어 보세요, not 읽으 보세요.

-세요 is a polite ending used for requests, suggestions, or instructions.

So 읽어 보세요 is polite and appropriate in many everyday situations:

• speaking to customers
• giving event instructions
• talking politely to someone you do not know well
• making a gentle request

It is not casual.
It is also not the most formal possible style.

Compare:

• 읽어 봐. = casual
• 읽어 보세요. = polite
• 읽어 보십시오. = more formal, official

In an event notice or spoken instruction, 읽어 보세요 sounds friendly and polite.

Korean word order is flexible, but this order is very natural.

The sentence is:

행사 전에 안내문을 자세히 읽어 보세요.

A rough structure is:

• 행사 전에 = time phrase
• 안내문을 = object
• 자세히 = adverb
• 읽어 보세요 = verb phrase

You can sometimes move parts around:

• 안내문을 행사 전에 자세히 읽어 보세요.
• 행사 전에 자세히 안내문을 읽어 보세요.

These are still understandable, but the original order sounds smooth and standard.

In Korean, the verb usually comes at the end, but things before it can move around for emphasis.

Yes, in standard writing, 읽어 보세요 with a space is very common and recommended.

That is because 보다 here is functioning as an auxiliary verb in the grammar -아/어 보다.

You may also see 읽어보세요 written together in real life. Korean spacing with auxiliary verbs is sometimes less strict in everyday writing, and both forms are seen. But for learners, 읽어 보세요 is a very good standard form to use.

A natural pronunciation is close to:

일거 보세요

That happens because 읽어 is pronounced as if the final consonant links into the following vowel sound.

So:

• written: 읽어
• pronounced: roughly 일거

This kind of sound change is very normal in Korean pronunciation. It is one reason spoken Korean can sound different from the spelling at first.

The overall tone is polite, helpful, and instructional.

It sounds like something you might hear or read:

• at an event
• in a notice
• from staff
• in a guide or announcement

Because it uses:

• 자세히 = carefully / in detail
• 읽어 보세요 = polite and slightly softened request

it feels less like a command and more like a courteous instruction.