अगर तुम जल्दी आओगी, तो हम समय पर स्टेशन पहुँचेंगे।

It is the Hindi if ... then ... pattern.

• अगर = if
• तो = then

So the structure is:

• अगर तुम जल्दी आओगी = if you come early
• तो हम समय par स्टेशन पहुँचेंगे = then we will reach the station on time

In Hindi, तो is very common in this kind of sentence, even when English would often leave out then.

आओगी is the future tense form of आना (to come) for tum when speaking to a female.

So:

• तुम आओगे = you will come (to a male)
• तुम आओगी = you will come (to a female)

The sentence is talking to one female person, so आओगी is the correct form.

That is a very common and important difference between English and Hindi.

In English:

• If you come early, we will reach on time.

In Hindi, it is normal to use a future form in the अगर clause:

• अगर तुम जल्दी आओगी, तो हम समय पर स्टेशन पहुँचेंगे।

So Hindi does not have to match English here.

Also, in everyday Hindi, you may sometimes hear a more subjunctive-style form:

• अगर तुम जल्दी आओ, तो हम समय पर स्टेशन पहुँचेंगे।

Both patterns can occur, but the sentence you were given is grammatically fine and very clear.

The verb आना (to come) is a little irregular.

For tum in the future, the forms are:

• आओगे = you will come (male)
• आओगी = you will come (female)

So the stem here is आओ-, followed by the future ending.

This is similar to some other common verbs:

• जाना → जाओगे / जाओगी
• करना → करोगे / करोगी

So आओगी is not random; it follows a recognizable future pattern.

Because the subject there is हम (we).

The verb पहुँचेंगे is the future form meaning will reach for we (or they) in a masculine/mixed-gender group.

So:

• मैं पहुँचूँगा / पहुँचूँगी = I will reach
• हम पहुँचेंगे = we will reach

If the group were understood as all female, you might also see:

• हम पहुँचेंगी

But पहुँचेंगे is very common as the default plural form, especially for mixed or unspecified groups.

Yes, you can leave it out in many cases.

So both of these are possible:

• अगर तुम जल्दी आओगी, तो हम समय पर स्टेशन पहुँचेंगे।
• अगर तुम जल्दी आओगी, हम समय पर स्टेशन पहुँचेंगे।

However, तो helps mark the result clause clearly, so learners will see it very often. It makes the if ... then ... relationship more explicit.

In this sentence, जल्दी most naturally means early.

So:

• जल्दी आओगी = you will come early

The word जल्दी can mean different things depending on context:

• quickly
• soon
• early

Here, because the result is reaching the station on time, the meaning is clearly about coming earlier than usual / early enough.

पर is the postposition used in the expression समय पर, which means on time.

This is a fixed and very common phrase:

• समय पर = on time
• वक़्त पर = on time

So you should learn समय पर as a unit.

It does not mean literally on the time in a word-for-word English way; it is just the normal Hindi expression.

Good question. In Hindi, with पहुँचना (to reach), the destination can often appear directly without a postposition:

• स्टेशन पहुँचेंगे = we will reach the station

But you may also hear:

• स्टेशन पर पहुँचेंगे

Both are possible, depending on style and emphasis. The version without पर is very natural.

So:

• समय पर = on time
• स्टेशन पहुँचेंगे = will reach the station

The पर in समय पर belongs to the time expression, not to स्टेशन.

Because तुम is the familiar, informal you.

Hindi has different levels of you:

• तू = very intimate / very informal
• तुम = familiar, neutral informal
• आप = polite / formal

So this sentence suggests the speaker is talking to someone they know fairly well.

If you wanted a polite version, you could say:

• अगर आप जल्दी आएँगी, तो हम समय पर स्टेशन पहुँचेंगे।

That would be used when speaking respectfully to a woman.

Yes, Hindi word order is somewhat flexible, though this version is very natural.

The basic order here is:

• अगर
  • subject + adverb + verb
• तो
  • subject + time phrase + destination + verb

So:

• अगर तुम जल्दी आओगी, तो हम समय पर स्टेशन पहुँचेंगे।

You might also hear small variations, such as moving स्टेशन earlier or later, but learners should stick to the given order because it is clear and standard.

A good beginner takeaway is:

• adverbs like जल्दी often come before the verb
• the main verb usually comes at the end of its clause