meonjeo muryo cheheomeul sincheonghaesseoyo.

먼저 means first, before that, or to begin with, depending on context.

In this sentence, it suggests something like:

• First, I signed up for the free trial
• I signed up for the free trial first

It often implies that this was the first step before some other action.

For example:

• 먼저 이름을 써 주세요. = Please write your name first.
• 먼저 먹어요. = Eat first.

So in your sentence, 먼저 sets the order of actions.

을 is the object particle. It marks 무료 체험 as the thing being applied for.

• 무료 체험 = free trial
• 무료 체험을 = the free trial as the object of the verb

The verb here is 신청했어요 (applied for / signed up for), and in Korean, the thing you apply for is marked as the object:

• 무료 체험을 신청했어요.

This is very common with 신청하다:

• 수업을 신청했어요. = I signed up for a class.
• 비자를 신청했어요. = I applied for a visa.

신청했어요 comes from the dictionary form 신청하다, which means to apply for or to sign up for.

Breakdown:

• 신청 = application / request
• 하다 = to do

Together:

• 신청하다 = to apply / to sign up

Then it changes to the polite past form:

• 신청하다 → 신청했어요

So 신청했어요 means:

• applied
• signed up
• requested

depending on the context.

Because the sentence is talking about something that has already been done.

• 신청해요 = apply / sign up or am applying (present, depending on context)
• 신청했어요 = applied / signed up (past)

So:

• 무료 체험을 신청해요. = I sign up for the free trial / I’m signing up for the free trial
• 무료 체험을 신청했어요. = I signed up for the free trial

Korean uses past tense when the action is completed.

Yes, the subject is most likely I, but Korean often leaves the subject out when it is obvious from context.

So this sentence could be understood as:

• (저는) 먼저 무료 체험을 신청했어요.
• I signed up for the free trial first.

In Korean, omitting the subject is very normal if the listener already knows who is being talked about.

Possible full version:

• 저는 먼저 무료 체험을 신청했어요.

But in everyday speech, leaving out 저는 sounds natural.

Korean word order is usually Subject - Object - Verb.

So this sentence follows the normal Korean pattern:

• (저는) = subject
• 먼저 = adverb
• 무료 체험을 = object
• 신청했어요 = verb

Literally, it is closer to:

• (I) first free trial applied-for

English usually puts the verb earlier:

• I signed up for the free trial first.

In Korean, the verb almost always comes at the end.

Yes. 먼저 is fairly flexible because it is an adverb.

For example, these are all possible:

• 먼저 무료 체험을 신청했어요.
• 무료 체험을 먼저 신청했어요.

Both mean roughly the same thing, but the emphasis can shift slightly:

• 먼저 무료 체험을 신청했어요.
  Focuses a bit more on first as the overall action order.
• 무료 체험을 먼저 신청했어요.
  Can put a bit more focus on the free trial being the thing that was done first.

Both are natural.

무료 체험 means free trial or free experience/use.

Breakdown:

• 무료 = free of charge
• 체험 = experience, trial, trying something out

So 무료 체험 is often used for:

• services
• apps
• classes
• memberships
• products you can try temporarily for free

Examples:

• 무료 체험 기간 = free trial period
• 무료 체험 수업 = free trial lesson

It sounds natural in ads, websites, and service sign-up situations.

These verbs are related, but they are not the same.

• 신청하다 = to apply for / sign up for / request

  • used when you are asking to join, receive, or use something
  • ex: 무료 체험을 신청했어요.

• 등록하다 = to register / enroll

  • often used when your name/info is officially entered into a system
  • ex: 학원에 등록했어요. = I enrolled in the academy.

• 예약하다 = to reserve / make a reservation

  • used for booking a time or place
  • ex: 호텔을 예약했어요. = I booked a hotel.

So 신청하다 fits 무료 체험 well because you are applying or signing up for access to it.

It can be either, depending on context.

• applied for sounds a little more formal
• signed up for sounds more natural for things like online services, lessons, memberships, and trials

So in many everyday contexts, a natural translation would be:

• I signed up for the free trial first.

But if the situation is more formal, applied for the free trial can also work.

Korean 신청하다 covers both ideas more broadly than any one English verb.

신청했어요 is in the polite informal style, often called the -아요/-어요 style.

It is polite and very common in everyday conversation.

Compare:

• 신청했어요 = polite, everyday standard
• 신청했습니다 = more formal
• 신청했어 = casual, used with close friends or younger people

So you could say:

• 먼저 무료 체험을 신청했어요. = polite
• 먼저 무료 체험을 신청했습니다. = formal
• 먼저 무료 체험을 신청했어. = casual

In casual speech, you may sometimes hear the object particle dropped, especially in conversation:

• 무료 체험 신청했어요.

People will still understand it. However, for learners, it is better to keep the particle:

• 무료 체험을 신청했어요.

That version is clearer and more standard.

Particle dropping is common in spoken Korean, but using the particle correctly will make your Korean more accurate, especially while learning.

Because 무료 체험 is a noun phrase, while 신청했어요 is a conjugated verb form.

• 무료 = adjective-like noun meaning free of charge
• 체험 = noun meaning trial/experience

Together they form the noun phrase 무료 체험.

But 신청했어요 is one verb expression from 신청하다, conjugated into past polite form, so it is written together.

This is very common in Korean:

• noun phrase: 한국 음식
• verb form: 먹었어요

So the spacing reflects the grammar.