Я промок под дождём и сразу пошёл домой.

Промок usually means got soaked / got drenched / got wet through, not just a little wet.

So in this sentence, the idea is stronger than simply I got wet. It suggests the rain really got to him.

• намок = got wet
• промок = got thoroughly wet, soaked through

In everyday use, промок is very common when talking about rain, shoes, clothes, etc.

The verb is промокнуть. In the past tense masculine singular, many Russian verbs in -нуть lose the -ну-:

• промокнуть → промок
• замёрзнуть → замёрз
• привыкнуть → привык

So я промок is the normal form.

Other past forms are:

• я промок — if the speaker is male
• я промокла — if the speaker is female
• мы промокли — we got soaked

Russian often can omit subject pronouns, but here я is helpful because the past tense does not show person.

Compare:

• промок = could mean I got soaked or he got soaked, depending on context
• пошёл = could mean I went or he went, depending on context

So я makes the subject clear right away.

Without context, Промок под дождём и сразу пошёл домой could sound incomplete or ambiguous. With context, though, Russians may drop я.

Yes, под literally means under, but in Russian под дождём is a very normal expression meaning in the rain or out in the rain.

So although the literal image is under the rain, the natural English translation is:

• in the rain
• out in the rain

This is just how Russian expresses that situation.

Because под takes different cases depending on meaning:

• под + instrumental = location/state: under
• под + accusative = movement to a position under something

Here, под дождём describes the situation someone was in, so Russian uses the instrumental.

That is why you get:

• дождь → дождём

This phrase is very common and is best learned as a set expression: под дождём = in the rain.

Because пошёл is perfective and fits a completed sequence of events:

• Я промок — I got soaked
• и сразу пошёл домой — and then I immediately went/set off home

Пошёл often means started going or set off.

If you said шёл, it would sound more like was walking or would focus on the process:

• Я промок под дождём и сразу шёл домой sounds wrong in this context.

So пошёл is the natural choice for then went home right away.

Literally, пойти / идти is the verb of going on foot. So yes, at a basic level it suggests walking.

But in real everyday Russian, пошёл домой is also often used more generally as went home / headed home, especially when the exact means of transport is not important.

If you want to make the transport explicit, Russian can use a different verb:

• поехал домой — went home by vehicle
• полетел домой — flew home

So in many ordinary contexts, пошёл домой is just the natural way to say went home.

Домой is a special adverb meaning home, to home, or homeward.

It is the normal word used with verbs of motion:

• идти домой — go home
• ехать домой — drive/go home
• вернуться домой — return home

Compare:

• домой = home
• в дом = into the house/building
• к дому = toward the house

So пошёл домой means went home, not specifically went into a house.

You would change the past tense forms to feminine:

• Я промокла под дождём и сразу пошла домой.

That is because Russian past tense agrees with gender in the singular:

• masculine: промок, пошёл
• feminine: промокла, пошла
• neuter: промокло, пошло
• plural: промокли, пошли

This is one of the first things English speakers notice, because English past tense does not do this.

Сразу means immediately, right away, or at once.

In this sentence, it modifies пошёл домой:

• и сразу пошёл домой = and immediately went home

Russian word order is flexible, so you may also see:

• Я сразу пошёл домой
• Я пошёл домой сразу

But the original version sounds very natural and neutral in a story-like sequence: first he got soaked, then he immediately went home.

Yes. Russian word order is much freer than English word order. The original sentence is neutral and natural:

• Я промок под дождём и сразу пошёл домой.

But other orders are possible, depending on emphasis:

• Под дождём я промок и сразу пошёл домой.
• Я под дождём промок и сразу пошёл домой.
• Я промок и сразу пошёл домой под дождём. — grammatically possible, but less natural because it can sound as if he went home while in the rain

So while Russian allows movement of words, not every order sounds equally natural. The original sentence is probably the best one for a learner to use.

The letter ё is pronounced yo and is always stressed.

So:

• дождём = roughly dozh-DYOM
• пошёл = roughly pa-SHYOL

In many real Russian texts, people write е instead of ё, so you may see:

• дождем
• пошел

But the pronunciation is still ё in these words. For learners, it is very helpful when ё is written, because it shows both pronunciation and stress.