Antes del seminario, quiero practicar la exposición con mi tutora.

Because de + el normally contracts to del in Spanish.

So:

• antes de el seminario → incorrect
• antes del seminario → correct

This contraction happens very often:

• vengo del trabajo
• hablamos del tema

One important exception: you do not contract when El is part of a proper name, such as El Escorial.

• antes de El Escorial → no contraction there

The phrase Antes del seminario is an introductory time expression. In Spanish, it is very common to place a comma after this kind of element, especially when it comes at the beginning of the sentence.

So this is natural:

• Antes del seminario, quiero practicar...

You may also see sentences without the comma in informal writing, but the comma is a good standard choice here.

After querer when it means to want to do something, the next verb stays in the infinitive.

Pattern:

• querer + infinitive

Examples:

• Quiero comer
• Quiero estudiar
• Quiero practicar

So in this sentence:

• quiero practicar = I want to practise

You only conjugate the first verb (quiero). The second verb (practicar) stays unchanged.

Quiero is the first-person singular present tense of querer.

• querer = to want
• quiero = I want

A few useful present-tense forms are:

• quiero = I want
• quieres = you want
• quiere = he/she wants
• queremos = we want
• queréis = you all want (Spain)
• quieren = they/you all want

It is an irregular verb, so the stem changes:

• quer- → quier- in several forms

Spanish uses the definite article more often than English, especially when talking about something already understood in the situation.

Here, la exposición suggests a specific presentation that both speaker and listener know about.

So Spanish naturally says:

• practicar la exposición

Even if English might prefer:

• practise my presentation
• practise the presentation

Spanish does not always need a possessive like mi if the context already makes it clear whose presentation it is.

Yes, in this context exposición can mean an oral presentation or talk.

This word has several meanings depending on context:

• exposición = exhibition
• exposición = exposure
• exposición = presentation / oral report

In academic contexts in Spain, hacer una exposición often means to give a presentation.

So here, practicar la exposición means practising the talk or presentation, not practising an exhibition.

Yes, and it would sound very natural.

There is a slight nuance:

• practicar = to practise, to work on it generally
• ensayar = to rehearse, often more specifically as a run-through

So:

• Quiero practicar la exposición = I want to practise the presentation
• Quiero ensayar la exposición = I want to rehearse the presentation

If you mean a full rehearsal, ensayar is often especially good.

Because tutora is the feminine form, used for a female tutor.

• tutor = male tutor
• tutora = female tutor

Spanish nouns referring to people often change form depending on gender:

• profesor / profesora
• doctor / doctora
• tutor / tutora

So if the tutor is a woman, mi tutora is correct.

Not necessarily.

In Spain, tutora often means someone who guides or supervises a student, such as:

• an academic tutor
• a personal tutor
• a supervisor for a project
• a form tutor in school

It is not always the same as profesora.

• profesora = teacher
• tutora = tutor / supervisor / academic adviser, depending on context

So mi tutora suggests a specific person helping guide the student, not just any teacher.

Yes. Con means with, and here it shows the person the speaker will practise together with.

• practicar la exposición con mi tutora = to practise the presentation with my tutor

This implies collaboration or at least that the tutor is present and helping.

In Spanish, when a possessive adjective like mi, tu, su, nuestro comes before the noun, you normally do not use an article.

So:

• mi tutora = correct
• la mi tutora = incorrect in standard modern Spanish

Compare:

• mi libro
• tu clase
• nuestra profesora

Spanish chooses either the possessive or the article here, not both.

Yes, Spanish has some flexibility in word order.

The original sentence is very natural:

• Antes del seminario, quiero practicar la exposición con mi tutora.

But other orders are possible, for example:

• Quiero practicar la exposición con mi tutora antes del seminario.
• Con mi tutora, quiero practicar la exposición antes del seminario.

The first version sounds the most neutral. Moving parts around usually changes emphasis, not the basic meaning.

A rough guide in Spain would be:

• Antes: AHN-tes
• del: del
• seminario: seh-mee-NA-ryo
• quiero: KYE-ro
• practicar: prak-tee-KAR
• la exposición: la eks-po-see-THYON in much of Spain
• con mi tutora: kon mi too-TO-ra

A few Spain-specific notes:

• c before i/e and z are often pronounced with the th sound of think in most of Spain
• so exposición often sounds like ekspo-see-THYON

If you are aiming for Spain Spanish, that pronunciation is useful to learn.