jeonhwa buseuneun yeyakjeraseo hwasang hoeui jeone yeyakhaeyo.

예약제 means a reservation-based system or by-reservation policy.

It is made from:

• 예약 = reservation, booking
• 제 = system, method, policy

So 예약제 does not just mean a reservation. It means the booth operates under a rule or system where people are expected to book it in advance.

This is the grammar pattern Noun + (이)라서, which means because it is...

• After a noun ending in a consonant, use 이라서
• After a noun ending in a vowel, use 라서

Since 예약제 ends in the vowel sound ㅔ, it becomes 예약제라서.

So:

• 학생이라서 = because I am a student
• 의사라서 = because I am a doctor
• 예약제라서 = because it is reservation-only / because it is a reservation system

는 is the topic marker.

In this sentence, 전화 부스는 sets up the phone booth as the topic: the sentence is explaining something about that booth.

So the structure is basically:

• As for the phone booth, it is reservation-only, so...

Using 는 can also give a slight contrastive feeling depending on context, such as:

• The phone booth is reservation-only, maybe unlike some other spaces.

The object is understood from context and left out.

In English, we usually repeat it:

• I reserve the phone booth before the video meeting.

In Korean, once 전화 부스 has already been introduced, it is very natural to omit it in the second part.

A fuller version would be:

• 전화 부스는 예약제라서 화상 회의 전에 전화 부스를 예약해요.

But repeating 전화 부스를 would sound less natural unless you want emphasis or extra clarity.

전에 means before.

It attaches to a noun phrase:

• 화상 회의 전에 = before the video meeting

This is an important pattern:

• Noun + 전에 = before the noun/event

Examples:

• 수업 전에 = before class
• 점심 전에 = before lunch
• 회의 전에 = before the meeting

If you want to say before doing something with a verb, Korean usually uses -기 전에:

• 회의하기 전에 = before having the meeting

Korean present tense often covers:

• habitual actions
• general routines
• near-future actions

So 예약해요 here can mean something like:

• I reserve it before video meetings
• I usually reserve it before a video meeting
• I will reserve it before the video meeting

The exact time comes from context. In this sentence, it most naturally sounds like a habitual or normal practice.

That is very normal in Korean.

The word 예약 is a noun meaning reservation, and it can appear in different related forms:

• 예약제 = reservation system / reservation-only policy
• 예약하다 = to make a reservation
• 예약해요 = make a reservation

English sometimes avoids repeating the same root, but Korean often keeps the same core word across related expressions. So this repetition sounds natural, not awkward.

Literally, yes: 전화 부스 means phone booth.

But in modern Korean usage, it can also refer to a small private booth for phone calls or online meetings, especially in:

• offices
• libraries
• coworking spaces
• public work areas

So it may not mean an old-fashioned public street phone booth. In this context, it probably means a small booth used for calls or video meetings.

Korean often drops the subject when it is already obvious from context.

So even though English would normally say:

• I reserve it before the video meeting

Korean can simply say:

• ...예약해요

The listener can infer the subject from the situation. If you wanted to make the subject explicit, you could say:

• 저는 전화 부스는 예약제라서 화상 회의 전에 예약해요.

But in many situations, that would sound unnecessary.

예약해요 is in the polite informal style, often called the -해요 style.

It is commonly used in everyday conversation and is polite enough for many normal situations.

Compare:

• 예약해요 = polite, natural, everyday
• 예약합니다 = more formal
• 예약해 = casual, plain speech to someone close

So this sentence sounds polite and conversational, not stiff or overly formal.