Таможенный пост находится рядом.

It is an official phrase meaning a customs post, customs checkpoint, or sometimes customs station/office, depending on context.

A learner might first think of English post in the sense of mail or a job position, but here пост means a station/checkpoint/post in an administrative or control sense.

So таможенный пост is a set phrase, especially in official or border-related contexts.

Таможенный is an adjective, and it agrees with пост.

Here:

• пост is masculine
• singular
• nominative case

So the adjective also has to be masculine singular nominative: таможенный.

Compare:

• таможенный пост — masculine
• таможенная служба — feminine
• таможенное оформление — neuter
• таможенные посты — plural

It is in the nominative case because it is the subject of the sentence.

The sentence is basically:

• Таможенный пост = the customs post
• находится рядом = is located nearby

So таможенный пост is the thing being talked about, which is why it stays in the nominative.

Because Russian does not usually use есть as a simple present-tense equivalent of English is in sentences like this.

Instead:

• есть often means there is / there exists
• for location, Russian often either omits the verb entirely or uses a verb like находиться

So:

• Таможенный пост находится рядом = The customs post is located nearby
• Таможенный пост рядом = The customs post is nearby

Both are possible, but находится sounds more explicit and a bit more formal.

Находится is the 3rd person singular present tense form of находиться.

That means it matches a singular subject:

• пост находится — the post is located

If the subject were plural, you would use:

• посты находятся — the posts are located

In modern Russian, находиться often simply means to be located.

Yes, absolutely.

Таможенный пост рядом is natural Russian and often sounds more conversational.

The version with находится:

• is a little more formal
• sounds more like official information, directions, or written language

So the difference is mostly one of style:

• Таможенный пост рядом — simpler, everyday
• Таможенный пост находится рядом — more formal/explicit

Here рядом means nearby, close by, or not far away.

Used by itself, it works as an adverb:

• Он рядом. — He is nearby.
• Таможенный пост рядом. — The customs post is nearby.

If you want to say next to or beside something specific, you usually use:

• рядом с + instrumental

For example:

• рядом с аэропортом — next to / near the airport

So in your sentence, рядом stands alone and simply means nearby.

Because рядом is being used without a following noun.

When рядом is followed by a place or object, you normally say:

• рядом с домом — next to the house
• рядом с границей — near the border

But if no noun follows, then с is not needed:

• Он рядом.
• Магазин рядом.
• Таможенный пост находится рядом.

So this sentence is complete as it is.

No, Russian word order is fairly flexible.

Таможенный пост находится рядом is a neutral, straightforward order.

You could also say:

• Рядом находится таможенный пост.

This version puts more attention on рядом first, almost like Nearby there is a customs post.

So changing the word order usually changes emphasis, not the basic meaning.

The stress is:

тамо́женный пост нахо́дится ря́дом

A few useful notes:

• тамо́женный — stress on о́
• нахо́дится — stress on хо́
• ря́дом — stress on я́

Also, the ending -тся in находится is pronounced roughly like ца in normal speech.

Because Russian has no articles.

So Таможенный пост находится рядом could mean:

• The customs post is nearby
• A customs post is nearby

Which one is intended depends on context.

English requires an article, but Russian does not.

It is natural Russian, but it sounds a bit formal/official because of:

• the phrase таможенный пост
• the verb находится

This kind of wording fits well in:

• announcements
• directions
• official descriptions
• travel/border contexts

In everyday speech, people might use a simpler version:

• Таможенный пост рядом.

Both are correct; the original just sounds more formal.