Мы быстро переобулись в тапочки и пошли на кухню пить чай.

That is true: Russian often leaves out subject pronouns when the verb form already makes the subject clear.

So this sentence could also be:

Быстро переобулись в тапочки и пошли на кухню пить чай.

But мы is still perfectly natural. It can be used:

• to make the sentence clearer on its own
• to set the scene at the start of a story
• to add a little emphasis to we

In an isolated example sentence, keeping мы is very normal.

Переобулись comes from переобуться and means changed shoes or changed into different footwear.

It is more specific than a general verb like got changed. It is used when someone switches from one pair of shoes to another, especially:

• outdoor shoes to indoor shoes
• regular shoes to slippers
• one pair of shoes to another for practical reasons

In this sentence, переобулись в тапочки means that they changed into slippers.

The ending -ся / -сь is the reflexive marker.

Here it shows that the subject did the action to themselves:

• переобуть кого-то = to change someone else’s shoes
• переобуться = to change one’s own shoes

So мы переобулись means we changed our shoes.

As for -сь vs -ся:

• they are the same reflexive ending
• -сь is commonly used after a vowel
• -ся is commonly used after a consonant

So переобулись is just the normal written form here.

Here в тапочки means into slippers, and тапочки is in the accusative plural.

After verbs that mean changing into something, Russian often uses:

• в + accusative

So:

• переобуться в тапочки = to change into slippers

Because тапочки is an inanimate plural noun, its accusative plural looks the same as the nominative plural:

• nominative: тапочки
• accusative: тапочки

That is why the form does not visibly change.

Russian word order is flexible, but this is a very normal neutral position.

Мы быстро переобулись... simply means we quickly changed shoes...

Putting быстро before the verb makes it sound smooth and natural in narration. You could move it, but the emphasis would change a little:

• Мы быстро переобулись = neutral
• Мы переобулись быстро = slightly more emphasis on the speed

So the sentence uses ordinary, natural word order.

Пошли comes from пойти, which is a perfective verb of motion. Here it means set off / went.

This is very common in Russian when telling a sequence of actions:

• first we changed shoes
• then we went to the kitchen

If you used шли, that would usually focus on the process of walking:

• мы шли на кухню = we were walking to the kitchen

But this sentence is not describing the process. It is moving the story forward from one completed step to the next, so пошли is the natural choice.

With кухня, Russian very often uses the pair:

• на кухню = to the kitchen
• на кухне = in the kitchen

This is simply the normal idiomatic choice in many contexts.

So:

• пошли на кухню = went to the kitchen

You may sometimes see в кухню, but it is less neutral and can sound more spatially literal, as if emphasizing entry into the room as a physical space. In everyday Russian, на кухню is the most natural choice here.

After verbs of motion, Russian often uses the infinitive to show purpose:

• пошли на кухню пить чай = went to the kitchen to drink tea

This structure is very common when the same people do both actions.

So the pattern is:

• go somewhere + infinitive
• идти / пойти куда-то делать что-то

For example:

• пошли в магазин купить хлеб
• поехали отдыхать

In this sentence, пить чай explains why they went to the kitchen.

Both переобулись and пошли are perfective because the sentence describes a sequence of completed events.

Russian often uses perfective verbs in narration to move from one finished action to the next:

• переобулись = changed shoes, completed
• пошли = set off / went, completed as the next step

If you used imperfective forms, the meaning would shift:

• переобувались = were changing shoes / used to change shoes
• шли = were walking

So perfective is the natural choice for a one-time chain of actions.

Because the subject is мы, and Russian past tense agrees with number.

For plural subjects, past-tense verbs take plural endings:

• мы переобулись
• мы пошли

In the plural, Russian past tense does not show gender.

Compare the singular:

• я переобулся = I changed shoes, masculine speaker
• я переобулась = I changed shoes, feminine speaker
• я пошёл = I went, masculine speaker
• я пошла = I went, feminine speaker

But with мы, you just use the plural form.

It literally means to drink tea, but in Russian it often has a slightly broader everyday feel, closer to have tea or sit down for tea.

Depending on context, it can suggest:

• drinking tea as a simple activity
• having tea together socially
• sitting in the kitchen with tea, possibly with snacks

So in this sentence, it is not just about the physical act of drinking. It can also evoke an ordinary home routine: changing into slippers, going to the kitchen, and having tea.