eki wo detara, massugu aruite kudasai.

This is a very common question, because English speakers often expect from here.

In Japanese, を is not only used for a direct object. It can also mark a place that someone passes through or leaves.

So:

• 駅を出る = to leave/exit the station
• 家を出る = to leave the house
• 部屋を出る = to leave the room

Here, 駅を出る is the natural way to say exit the station.

You may also see から with places, but 駅から出る is less standard in this kind of simple direction-giving sentence. 駅を出る is the usual expression.

出たら is the たら form of 出る.

• 出る = to go out / to exit
• 出た = exited / went out
• 出たら = if/when/after exiting

In this sentence, 出たら means something like:

• when you exit the station
• after you leave the station
• once you come out of the station

So the sentence is giving directions in sequence: first exit the station, then walk straight.

This is because たら is a grammar pattern that attaches to the plain past form of a verb.

So:

• 出る → plain form
• 出た → plain past form
• 出たら → if/when/after exiting

Even though 出た by itself looks past, in たら grammar it does not necessarily mean past time. It often means if, when, or after.

So this is not really saying after you exited in the past. It is saying when/after you exit.

It can mean all of those depending on context.

For this sentence, the most natural English idea is:

• when you exit the station
• after you exit the station
• once you leave the station

It is not really a doubtful if here, because the speaker expects you to do it. This is a directions sentence, so when/after fits better than if.

まっすぐ means straight or straight ahead.

In this sentence, it works like an adverb, modifying 歩いてください:

• まっすぐ歩く = to walk straight
• まっすぐ行く = to go straight

It usually means without turning.

So here it means: after exiting the station, go straight ahead.

歩いてください is a polite request form.

It is built like this:

• 歩く = to walk
• 歩いて = te-form
• 歩いてください = please walk

This form is very common for instructions and directions.

So:

• 歩きます = I walk / will walk / walk politely
• 歩く = walk (plain form)
• 歩いてください = please walk

Because the speaker is telling someone what to do, 〜てください is the right pattern.

Yes, 行く could also work.

• まっすぐ歩いてください = please walk straight
• まっすぐ行ってください = please go straight

The difference is small here:

• 歩く focuses on the physical act of walking
• 行く focuses more generally on going/moving

In directions, 行ってください is often more common, but 歩いてください is perfectly natural if the speaker wants to emphasize that you should continue on foot.

Yes. Japanese often leaves out the subject when it is obvious from context.

In a directions sentence like this, the implied subject is basically:

• you

So the full idea is:

• When you leave the station, please walk straight.

But Japanese does not need to say あなたは here.

Yes, and that is also natural.

There is a small nuance difference:

• 駅を出たら、まっすぐ歩いてください

  • When/after you exit the station, walk straight
  • slightly emphasizes the point after exiting

• 駅を出て、まっすぐ歩いてください

  • Exit the station and walk straight
  • sounds like a simple sequence of actions

Both are good for directions. The たら version highlights the moment after the first action is completed.

It is polite, neutral instruction language.

The key polite part is:

• ください = please

This makes it appropriate for:

• giving directions
• helping a stranger
• written instructions
• announcements

It is polite, but not extremely formal. It sounds normal and useful in everyday situations.

The comma separates the two parts of the sentence:

• 駅を出たら、
• まっすぐ歩いてください。

It marks a natural pause, like:

• When you exit the station, please walk straight.

Japanese commas are often used more flexibly than English commas, but here it helps make the structure easier to read.

The structure is:

• [Clause 1] + たら, [Clause 2]
• When/after [Clause 1], [do Clause 2].

Applied here:

• 駅を出たら = when you leave the station
• まっすぐ歩いてください = please walk straight

So the whole pattern is:

• When you leave the station, please walk straight.

This is a very common pattern for giving instructions in steps.