gēngyīshì zài línyùshì pángbiān.

The pattern is:

Place A + 在 + Place B + 旁边

So in this sentence:

• 更衣室 = the changing room
• 在 = is located at / is in
• 淋浴室 = the shower room
• 旁边 = beside / next to

So the structure means:

The changing room is beside the shower room.

A good way to remember it is:

[thing you are talking about] + 在 + [reference place] + [location word]

在 is commonly used to show location.

In this sentence, it works like is at / is in / is located at in English:

• 更衣室在淋浴室旁边。
• The changing room is next to the shower room.

It can also be used before a place in other kinds of sentences:

• 我在学校。 = I am at school.
• 书在桌子上。 = The book is on the table.

So here, 在 connects 更衣室 to its location.

旁边 means beside, next to, or at the side of.

It is a location word. Chinese often uses these words after a place noun:

• 桌子上 = on the table
• 椅子后面 = behind the chair
• 门口 = at the doorway
• 淋浴室旁边 = next to the shower room

So 旁边 tells you the position relative to 淋浴室.

Yes, you can say 淋浴室的旁边, but in many simple location phrases, 的 is often omitted.

So both are possible:

• 在淋浴室旁边
• 在淋浴室的旁边

The version without 的 is very common and natural in everyday Chinese.

A rough idea:

• 淋浴室旁边 = a compact, natural location phrase
• 淋浴室的旁边 = also correct, sometimes a little more explicit

For learners, it is very useful to get used to patterns like:

• 在学校附近
• 在桌子上
• 在门口
• 在房子后面

These often appear without 的.

Not exactly.

• 旁边 is the common word meaning beside / next to / by the side
• 旁 by itself is less commonly used in basic everyday speech for this meaning

For most beginner situations, use 旁边.

Example:

• 银行在超市旁边。 = The bank is next to the supermarket.

That will sound more natural than trying to use 旁 alone.

Yes. If two things are next to each other, the relationship works both ways.

So you can also say:

淋浴室在更衣室旁边。

That means:

The shower room is next to the changing room.

Chinese allows either version depending on which place you want to talk about first.

更衣室 can be broken down like this:

• 更衣 = to change clothes
• 室 = room

So literally it is something like clothes-changing room, which is why it means changing room or locker room, depending on context.

A lot of place words in Chinese are built this way:

• 教室 = classroom
• 办公室 = office
• 会议室 = meeting room
• 浴室 = bathroom / bath room

So learning 室 as room is very helpful.

淋浴室 breaks down like this:

• 淋浴 = shower
• 室 = room

So literally it means shower room.

Again, 室 tells you it is a room or enclosed space.

This kind of compound vocabulary is very common in Chinese, and recognizing the parts can make new words easier to remember.

Here it is pronounced gēngyīshì.

That is important because 更 can have different pronunciations in different words:

• 更 gēng in 更衣 = to change clothes
• 更 gèng often means more / even more, as in 更好 = better

So in this sentence, use gēng.

The full pronunciation is:

• 更衣室 = gēngyīshì
• 淋浴室 = línyùshì
• 旁边 = pángbiān

You can think of it as functioning like a main verb of location in this sentence.

In:

更衣室在淋浴室旁边。

在 means is located at.

In other sentences, 在 can also act more like a preposition before a place:

• 我在学校学习。 = I study at school.

For beginners, the most practical approach is:

• In a sentence like A 在 B 旁边, treat 在 as meaning is located at
• In a sentence like 我在学校吃饭, treat 在 as at/in

You do not need to worry too much about the grammar label at first; the key is understanding how it works in the pattern.

Chinese often does not need a separate verb like English is in the same way.

For location, Chinese commonly uses 在 directly:

• 我在家。 = I am at home.
• 书在桌子上。 = The book is on the table.
• 更衣室在淋浴室旁边。 = The changing room is next to the shower room.

So instead of thinking where is the word for is?, it is better to think:

在 already carries the location meaning that English expresses with is + preposition.

Sometimes in loose English translation, yes, but next to or beside is usually better here.

Why?

• 旁边 suggests something is at the side of something else
• near can be less exact and can mean a little farther away

So:

• 更衣室在淋浴室旁边。 = The changing room is next to the shower room.

If you say near, the meaning is not terribly wrong, but it is less precise.

Yes, very naturally.

This kind of sentence is common when:

• describing where rooms are
• reading maps or signs
• giving directions inside a building
• answering Where is ... ?

For example:

• 厕所在哪儿？ = Where is the restroom?
• 厕所在更衣室旁边。 = The restroom is next to the changing room.

So the sentence pattern is very useful in real life.

Yes. This is a very important pattern in Chinese. Some common location words are:

• 上面 = on top of / above
• 下面 = under / below
• 前面 = in front of
• 后面 = behind
• 里面 = inside
• 外面 = outside
• 左边 = on the left
• 右边 = on the right
• 中间 = in the middle
• 附近 = nearby

Examples:

• 书在桌子上面。 = The book is on the table.
• 学校在银行后面。 = The school is behind the bank.
• 商店在地铁站附近。 = The shop is near the subway station.

So 旁边 belongs to a very common and useful group of words.