È finito il caffè, quindi bevo tè caldo.

Both are correct.

• Il caffè è finito is the more neutral, straightforward word order: The coffee is finished / gone.
• È finito il caffè is very natural Italian too, and it often puts a little more focus on the fact that the coffee has run out.

Italian word order is more flexible than English word order, especially in sentences like this. English usually prefers The coffee is gone, while Italian can comfortably say either version.

Here è finito means has finished / is finished / has run out, depending on context.

In this sentence, il caffè is not the thing doing the action in the English sense. Instead, Italian uses finire in a way that means something comes to an end or is used up:

• È finito il caffè = The coffee is gone / We’ve run out of coffee

So finito is the past participle of finire, used with essere.

Because this is finire used intransitively: the coffee itself has come to an end.

Italian uses:

• essere with many intransitive verbs of change of state or movement
• avere with transitive uses

Compare:

• Il caffè è finito. = The coffee is gone / has run out.
• Ho finito il caffè. = I finished the coffee.

So:

• è finito = it is finished / it ran out
• ha finito would usually need a person as subject, like Luca ha finito il caffè = Luca finished the coffee

Because it agrees with il caffè, which is masculine singular.

With essere, the past participle usually agrees with the subject:

• Il caffè è finito → masculine singular
• La pizza è finita → feminine singular
• I panini sono finiti → masculine plural
• Le arance sono finite → feminine plural

So finito matches il caffè.

This is a very common thing learners notice.

il caffè

Here it refers to the coffee supply / the coffee we had available, so the definite article sounds natural:

• È finito il caffè = The coffee is gone

tè caldo

After bere, Italian often omits the article when speaking generally about what someone drinks:

• Bevo tè caldo = I drink/am drinking hot tea
• Mangio pane
• Bevo acqua

If you add an article, the meaning becomes more specific:

• Bevo il tè caldo could mean I’m drinking the hot tea or contrast it with cold tea, depending on context.

So in your sentence, no article before tè caldo is very natural.

Italian often uses the present tense where English might use several different forms depending on context.

• bevo can mean I drink or I’m drinking
• In this sentence, it means something like so I’m drinking hot tea or so I drink hot tea instead

Why not berrò?

• berrò = I will drink
• That would sound more clearly future: The coffee is gone, so I’ll drink hot tea

Why not sto bevendo?

• sto bevendo emphasizes the action happening right now: I am drinking
• Italian uses this form less often than English uses am drinking

So bevo is the most natural broad choice here.

Quindi means therefore, so, thus, or as a result.

In this sentence:

• È finito il caffè, quindi bevo tè caldo.
• The coffee is gone, so I drink/am drinking hot tea.

It connects cause and result.

A few similar connectors are:

• quindi = therefore / so
• allora = so / then
• perciò = therefore
• per questo = for this reason

In everyday speech, quindi is very common and natural.

Because adjectives in Italian often come after the noun.

So:

• tè caldo = hot tea
• caffè freddo = cold coffee
• vino rosso = red wine

Some adjectives can come before the noun, but ordinary descriptive adjectives like caldo usually come after it.

Yes, absolutely.

• bevo tè caldo = very natural, general, simple
• bevo del tè caldo = also natural, with a partitive sense, like I’m drinking some hot tea

Both work. The version without del is often more streamlined and common in general statements.

Yes. Il caffè is grammatically singular.

Italian often uses a singular noun for a substance or drink:

• il caffè
• il latte
• il tè
• il vino

So È finito il caffè literally treats coffee as a single mass noun: the coffee is finished/gone.

Yes, that is a very good natural interpretation.

Depending on context, the sentence can sound like:

• The coffee has run out, so I’m drinking hot tea
• There’s no more coffee, so I drink hot tea
• The coffee is gone, so I’ll have hot tea instead

The exact English wording changes a bit, but the Italian structure is perfectly natural for that idea.