Тот мужчина у окна читает газету и пьёт кофе.

Тот literally means that. In this sentence, Тот мужчина means that man.

A native English speaker may feel that it is acting a bit like the, because Russian has no articles (a / an / the). But тот is more specific and more demonstrative than the. It points something out.

So:

• мужчина = man / the man / a man depending on context
• тот мужчина = that man

Мужчина is in the nominative case because it is the subject of the sentence — the person doing the actions.

He is the one who:

• читает = reads
• пьёт = drinks

So the basic subject form is used:

• мужчина = man (subject form)

Also, although мужчина ends in -а, it refers to a male person and behaves as a masculine noun.

У окна means by the window or near the window.

The preposition у requires the genitive case, so окно changes to окна.

• окно = window
• у окна = by the window / near the window

This is a very common pattern:

• у дома = by the house
• у двери = by the door
• у окна = by the window

So the form changes because of the preposition у.

Читает is the 3rd person singular present-tense form of читать (to read).

The subject is тот мужчина = that man, so in English we say he reads / is reading. Russian uses:

• я читаю = I read / am reading
• ты читаешь = you read / are reading
• он / она читает = he / she reads / is reading

So читает matches a singular third-person subject.

Because газета is the direct object of читает, and direct objects often take the accusative case.

• dictionary form: газета = newspaper
• accusative singular: газету

So:

• читает газету = reads a newspaper / the newspaper

This is a very common feminine noun pattern:

• книга → книгу
• машина → машину
• газета → газету

Пьёт is the 3rd person singular form of пить (to drink).

The letter ё is important here because it shows both the pronunciation and the correct form:

• пить = to drink
• пьёт = he/she drinks, is drinking

In printed Russian, ё is sometimes written as е, so you may also see пьет, but пьёт is the more precise spelling.

Кофе is one of those Russian nouns that usually does not change form in the singular.

So:

• кофе = coffee
• пьёт кофе = drinks coffee

Even though it is the object of the verb, the word stays кофе.

It can mean either, depending on context.

Russian present tense often covers both:

• he reads
• he is reading

So читает газету и пьёт кофе can mean:

• reads a newspaper and drinks coffee
• is reading a newspaper and drinking coffee

In many everyday contexts, English would naturally translate this as the continuous form: is reading ... and drinking ...

In Russian, the present tense of to be is usually not expressed.

English says:

• The man is by the window.
• The man is reading.

Russian usually just says:

• Мужчина у окна.
• Мужчина читает.

So in your sentence, no separate word for is is needed.

Yes, Russian word order is more flexible than English.

This order is natural and straightforward:

• Тот мужчина = the topic/person
• у окна = location
• читает газету и пьёт кофе = actions

But Russian can move things around for emphasis. For example:

• Тот мужчина читает газету и пьёт кофе у окна.
• У окна тот мужчина читает газету и пьёт кофе.

These all have basically the same core meaning, but the emphasis changes slightly.

Russian has no articles, so there is no direct equivalent of a / an / the.

Whether газету means:

• a newspaper
• the newspaper

depends on context.

Likewise, кофе can mean simply coffee, without an article.

This is one of the biggest differences from English: Russian often leaves definiteness unstated unless it needs to be made clear by context or words like этот (this) or тот (that).

Yes. И is the standard Russian word for and.

So:

• читает газету и пьёт кофе = reads a newspaper and drinks coffee

It simply joins the two actions together.