Prefiero sentarme más atrás para ver mejor la pantalla.

In Spanish, subject pronouns are often omitted because the verb ending already tells you who the subject is.

• Prefiero already means I prefer
• So yo prefiero is possible, but usually only used for emphasis, contrast, or clarity

For example:

• Prefiero sentarme atrás. = neutral
• Yo prefiero sentarme atrás. = I prefer to sit at the back, maybe unlike someone else

Because preferir is a stem-changing verb in the present tense.

The e in the stem changes to ie in most present-tense forms:

• yo prefiero
• tú prefieres
• él/ella prefiere
• nosotros preferimos
• vosotros preferís
• ellos prefieren

This is very common in Spanish. A similar pattern happens with verbs like querer → quiero and pensar → pienso.

Because the verb here is sentarse, not just sentar.

• sentarse = to sit down / to take a seat
• sentar = to seat someone, or sometimes to suit someone

So:

• Prefiero sentarme = I prefer to sit down
• Prefiero sentar... would sound incomplete or would suggest seating someone else

The me is the reflexive pronoun, and it refers back to the speaker.

When a reflexive pronoun goes with an infinitive, Spanish normally attaches it to the end:

• sentar + me = sentarme

So prefiero sentarme is the normal structure.

English speakers often want to say something like prefiero me sentar, but that is not correct here.

Atrás means back or behind, and más atrás means further back or more toward the back.

In this sentence, it refers to where the speaker wants to sit.

So:

• atrás = at the back / behind
• más atrás = further back

This is a very natural way to talk about seats in a classroom, cinema, meeting room, etc.

Because para + infinitive expresses purpose, meaning in order to.

So:

• para ver mejor la pantalla = in order to see the screen better

This tells you why the speaker prefers to sit further back.

A very useful pattern is:

• para + infinitive = to / in order to

Examples:

• Estudio para aprender. = I study to learn.
• Voy temprano para evitar tráfico. = I go early to avoid traffic.

Because mejor is the correct word to modify the verb ver.

Here, mejor means better, as an adverb:

• ver mejor = to see better

You cannot use bueno here, because bueno is an adjective and normally describes nouns, not verbs.

Compare:

• una buena pantalla = a good screen
• ver mejor la pantalla = to see the screen better

So in this sentence, mejor describes how you see.

Spanish uses the definite article much more often than English.

Here, la pantalla means the screen, and it sounds natural because both speaker and listener are assumed to know which screen is being talked about — for example, the screen in the room.

English often leaves the article out in places where Spanish keeps it.

So:

• ver mejor la pantalla = see the screen better

Using pantalla without la would sound less natural in this sentence.

Sometimes yes, but the meaning is slightly different.

• más atrás = further back
• al fondo = at the very back

So más atrás is more relative: it just means moving back from where you are now or from another possible seat.

Al fondo is more absolute: it suggests the back end of the room.

Examples:

• Prefiero sentarme más atrás. = I prefer to sit further back.
• Prefiero sentarme al fondo. = I prefer to sit at the very back.

Yes. Spanish word order is flexible, especially when you want to emphasize a different part of the sentence.

For example, this is also natural:

• Para ver mejor la pantalla, prefiero sentarme más atrás.

That version puts the purpose first:

• To see the screen better, I prefer to sit further back.

The original sentence is also completely natural:

• Prefiero sentarme más atrás para ver mejor la pantalla.

The difference is mainly one of focus, not basic meaning.