Ở quán đó không có mạng, nên tôi phải về nhà để gửi địa chỉ cho người giao hàng.

Yes, ở can mean to live/stay, but in this sentence it means at / in and marks the location:

Ở quán đó = at that café / restaurant / shop

So here it is not the verb to live. It is introducing the place where the situation happens.

Compare:

• Tôi ở Hà Nội. = I live in Hanoi.
• Ở quán đó không có mạng. = At that café, there is no internet/signal.

The meaning depends on context.

Starting with Ở quán đó puts the location first, like As for that café... or At that café...

Both are possible, but they feel a little different:

• Ở quán đó không có mạng.
  = At that café, there was no internet.
• Quán đó không có mạng.
  = That café didn’t have internet.

The version with ở sounds a bit more like setting the scene first. Vietnamese often puts time or place expressions at the beginning of the sentence.

Quán is a very common Vietnamese word for a casual eating or drinking place, depending on context. It can mean things like:

• café
• eatery
• small restaurant
• shop/stall in some contexts

So quán đó means that place / that café / that shop, depending on the situation.

It is less formal than nhà hàng, which more specifically means restaurant.

Mạng literally means network, but in everyday speech it often refers to:

• internet access
• mobile data/signal
• connection in general

So không có mạng can mean:

• there was no internet
• there was no connection
• there was no signal

It does not always mean Wi‑Fi specifically. If someone wants to be more specific, they might say:

• không có Wi‑Fi
• không có internet
• mất mạng = the connection is down / no internet

In your sentence, không có mạng most naturally means there was no usable internet/connection there.

Có means to have / there is / there are.
So không có means do not have / there is not / there are not.

In this sentence:

Ở quán đó không có mạng
literally: At that café, there was not network/connection

You need có here because the idea is existence/availability, not just simple negation of an adjective or action.

Compare:

• Tôi không biết. = I do not know.
• Ở đây không có nước. = There is no water here.
• Quán đó không có mạng. = That café does not have internet.

Nên here means so / therefore / that’s why. It connects the cause and the result.

Structure:

• cause + nên
  • result

In your sentence:

• Ở quán đó không có mạng = there was no internet at that café
• nên tôi phải về nhà = so I had to go home

So the whole connection is: There was no internet there, so I had to go home...

A small note: nên can also have another meaning, should, in other sentences:

• Bạn nên nghỉ ngơi. = You should rest.

But in your sentence, it clearly means so / therefore.

Phải usually means must / have to.

In this sentence: tôi phải về nhà = I had to go home

It expresses necessity, not desire. The speaker did not simply choose to go home for fun; they needed to do it because there was no connection.

Compare:

• Tôi về nhà. = I go home / I went home.
• Tôi phải về nhà. = I have to / had to go home.

In context, English often translates it as had to, because the whole sentence describes a completed situation.

Về by itself already means go back / return. So:

• về nhà = go home / return home

You do not need đi here. Adding đi is usually unnecessary, and in many cases it would sound unnatural.

Compare:

• Tôi về nhà. = I’m going home.
• Tôi đi học. = I go to school.
• Tôi đi về nhà is generally not the normal way to say go home.

Think of về as already containing the idea of movement back toward a familiar place.

Để here means in order to / to, and it introduces purpose.

So: tôi phải về nhà để gửi địa chỉ...
= I had to go home in order to send the address...

This is a very common structure:

• làm gì đó để + verb
• do something to / in order to do something else

Examples:

• Tôi học tiếng Việt để nói chuyện với bạn bè.
  = I study Vietnamese to talk with friends.
• Anh ấy ra ngoài để mua đồ ăn.
  = He went out to buy food.

Cho here means to / for and marks the recipient of the action.

So:

• gửi địa chỉ = send the address
• cho người giao hàng = to the delivery person

Together: gửi địa chỉ cho người giao hàng = send the address to the delivery person

This is a very common pattern:

• đưa cái gì cho ai = give something to someone
• gửi cái gì cho ai = send something to someone
• nói cái gì cho ai = say something to someone

Người giao hàng literally means the person who delivers goods.

So it means:

• delivery person
• delivery driver/courier
• the person bringing the order

Breakdown:

• người = person
• giao hàng = deliver goods / make a delivery

In everyday Vietnamese, many people also say shipper, especially in cities, because English loanwords are common in this context. But người giao hàng is clear, standard, and fully Vietnamese.

Địa chỉ means address in general. It can be:

• a home address
• a company address
• a pickup/drop-off address
• sometimes even an online address in other contexts, though physical address is most common

In this sentence, it most likely means the speaker needed to send their delivery address or exact location to the delivery person.

Vietnamese often follows this order:

verb + object + recipient

So:

• gửi = send
• địa chỉ = the address
• cho người giao hàng = to the delivery person

That makes: gửi địa chỉ cho người giao hàng

This is very natural Vietnamese word order.

Compare:

• Tôi đưa tiền cho anh ấy. = I give money to him.
• Cô ấy gửi tin nhắn cho tôi. = She sends a message to me.

No. Tôi is just a neutral, fairly formal way to say I.

Other pronouns could be used depending on the speaker’s age, gender, relationship, and situation, for example:

• mình
• em
• anh
• chị
• tao (very informal, only in certain relationships)
• sometimes the person’s role or name instead of I

So the sentence uses tôi because it is safe, neutral, and easy for learners.

It is natural and clear. It follows a very common Vietnamese logic:

• location/problem first
• consequence next
• purpose last

Breakdown:

• Ở quán đó không có mạng = problem/background
• nên tôi phải về nhà = result
• để gửi địa chỉ cho người giao hàng = purpose

A very literal gloss would be:

At that café there was no connection, so I had to go home to send the address to the delivery person.

That is a normal and well-formed Vietnamese sentence.