En octubre, mi hermana quiere volver a la universidad.

In Spanish, months are normally used without the definite article after en when you mean in + month.

• en octubre = in October
• en mayo = in May
• en diciembre = in December

So En octubre is the normal way to say In October.

You may sometimes see an article in other contexts, but in a simple time expression like this, en octubre is the standard form.

Spanish often places a time expression at the beginning of the sentence, just like English can:

• En octubre, mi hermana quiere volver a la universidad.
• Mi hermana quiere volver a la universidad en octubre.

Both are correct. Starting with En octubre gives a little more emphasis to when it will happen.

The comma is also natural here because the sentence begins with a time phrase.

Mi hermana means my sister.

In Spanish, possessives usually go before the noun:

• mi hermano = my brother
• mi hermana = my sister
• mi casa = my house

Unlike English, you do not say something like hermana mi in normal usage. The standard order is:

• mi + noun

There is also a different, more emphatic structure like la hermana mía, but that is not the normal choice here.

Quiere is the third-person singular form of the verb querer in the present tense.

The subject is mi hermana, which is she, so the verb has to match that subject:

• yo quiero = I want
• tú quieres = you want
• él / ella quiere = he / she wants

So:

• mi hermana quiere = my sister wants

Querer is the infinitive, meaning to want, so it cannot be used as the main conjugated verb here.

After a conjugated verb like quiere, Spanish normally uses an infinitive for the next verb.

So:

• quiere volver = wants to return / wants to go back
• not quiere vuelve

This is the same pattern as in English:

• She wants to return
• not She wants returns

Very common examples:

• quiero comer = I want to eat
• queremos salir = we want to go out
• mi hermana quiere estudiar = my sister wants to study

Here, volver means to return, to go back, or to come back, depending on context.

So quiere volver a la universidad means:

• she wants to return to university
• she wants to go back to university

Volver is a very common verb in Spanish.

Examples:

• volver a casa = to go back home
• volver al trabajo = to go back to work

The preposition a is used after volver when you say where someone returns to.

• volver a casa = return home
• volver al colegio = return to school
• volver a la universidad = return to university

So the a here corresponds to English to.

In Spanish, it is very common to use the definite article with places and institutions in cases like this.

So:

• a la universidad = to the university / to university

Even when English often drops the article, Spanish frequently keeps it:

• voy a la escuela = I go to school
• vuelve al trabajo = he returns to work
• entra en la oficina = she goes into the office

In Spain, la universidad can often be translated naturally as university or college, depending on context, but Spanish still normally uses the article here.

A la is simply:

• a = to
• la = the

They stay separate because la is feminine.

• a + el = al
• a + la = a la

So compare:

• volver al trabajo = return to work
• volver a la universidad = return to university

Since universidad is feminine, you must use la, not el.

Because it takes the article la:

• la universidad

Many nouns ending in -dad are feminine:

• la ciudad = city
• la posibilidad = possibility
• la universidad = university

So when you learn universidad, you should learn it together with its article:

• la universidad

That helps you remember gender naturally.

Spanish often uses the present tense to talk about a planned or intended future action, especially when there is a clear time expression.

Here, En octubre makes the future time clear, so quiere is perfectly natural.

This works similarly to English:

• In October, my sister wants to go back to university.

Depending on context, English might prefer is going to want to less often, but Spanish commonly uses the present in this kind of sentence.

The idea is:

• now, she has that desire/intention
• the return happens in October

Yes. This is a very useful point.

Volver a + place/noun usually means return to:

• volver a la universidad = return to university

But volver a + infinitive means do something again:

• volver a estudiar = study again
• volver a intentarlo = try again

So compare:

• Mi hermana quiere volver a la universidad.
  = My sister wants to return to university.

• Mi hermana quiere volver a estudiar.
  = My sister wants to study again.

The structure after a tells you which meaning is intended.

A simple Spain Spanish pronunciation guide would be:

• quiere ≈ KYE-reh
• volver ≈ bol-BER
• a la ≈ a la
• universidad ≈ oo-nee-behr-see-DAD

A few useful pronunciation points:

• qu before i/e sounds like a hard k:
  quiere → kye-
• v and b are pronounced very similarly in Spanish.
• The stress in universidad falls on the last syllable:
  u-ni-ver-si-DAD

In Spain, the z sound in words like universidad is pronounced with the th sound of think at the end:

• universidad ≈ oo-nee-behr-see-THAD

Yes. Regresar can also mean to return/go back.

So this is possible:

• En octubre, mi hermana quiere regresar a la universidad.

However, volver is extremely common and very natural in everyday Spanish.

Depending on region and style, one may sound slightly more common than the other, but in Spain, volver is very standard and natural in this sentence.