Me gusta que la narradora explique el argumento con calma y sin complicar demasiado las cosas.

Because gustar works differently from to like in English.

In Spanish, gustar literally works more like to be pleasing to someone. So:

• Me gusta... = It is pleasing to me... / I like...

Here, what is being liked is the whole idea introduced by que:

• que la narradora explique el argumento...

That whole clause is treated as a singular idea, so Spanish uses gusta.

Because the thing being liked is not a plural noun, but a whole clause:

• que la narradora explique el argumento con calma...

When gustar is followed by an infinitive or a full que + clause, Spanish normally uses singular gusta, because the entire action or situation is treated as one thing.

Compare:

• Me gusta el libro. = I like the book.
• Me gustan los libros. = I like the books.
• Me gusta leer. = I like reading.
• Me gusta que hables despacio. = I like that you speak slowly.

Here que introduces a subordinate clause:

• que la narradora explique el argumento...

It is equivalent to that in English, although English often leaves that out:

• I like that the narrator explains the plot calmly...
• or more naturally, I like the narrator explaining the plot calmly...

In Spanish, que is required here.

Because after me gusta que, Spanish normally uses the subjunctive.

The structure is:

• gustar + que + subjunctive

So:

• Me gusta que la narradora explique...

and not:

• Me gusta que la narradora explica...

This happens because the speaker is expressing a personal reaction, feeling, or evaluation about someone else’s action. That kind of structure commonly triggers the subjunctive.

Other examples:

• Me gusta que vengas. = I like that you come.
• No me gusta que hablen tan alto. = I don’t like that they speak so loudly.

Explique is the present subjunctive form of explicar for ella / usted.

The subject is:

• la narradora = she

So:

• la narradora explique

Present subjunctive of explicar:

• yo explique
• tú expliques
• él/ella/usted explique
• nosotros expliquemos
• vosotros expliquéis
• ellos/ellas/ustedes expliquen

Notice the spelling change from c to qu to keep the hard k sound before e.

This is a spelling change to preserve pronunciation.

If Spanish wrote explice, the c before e would sound like the th in Spain or s in much of Latin America. But explicar has a hard k sound.

So in forms before e, Spanish changes:

• c → qu

That is why:

• explicar → explique
• saque from sacar
• toque from tocar

It is only a spelling change, not an irregular pronunciation change.

Because sin is a preposition, and after a preposition Spanish normally uses the infinitive when the subject stays the same.

So:

• sin complicar demasiado las cosas = without making things too complicated

Here, the person doing both actions is the same:

• the narrator explains
• the narrator does so without complicating things too much

That is why Spanish uses complicar, not a finite verb like complica.

Compare:

• Entró sin hablar. = He/she came in without speaking.
• Estudia sin escuchar música. = He/she studies without listening to music.

Con calma literally means with calm, but in natural English it usually means:

• calmly
• at a relaxed pace
• without rushing

So explicar el argumento con calma suggests that the narrator explains the plot in a clear, patient, unhurried way.

It is a very common Spanish expression:

• Hazlo con calma. = Do it calmly / Take your time with it.

Las cosas literally means the things, but in many contexts it is a very general expression meaning:

• things
• matters
• the situation
• what is being discussed

In sin complicar demasiado las cosas, it means something like:

• without making things too complicated
• without overcomplicating things

Spanish often uses las cosas in this broad, natural way.

Here demasiado modifies the verb idea complicar:

• complicar demasiado las cosas = to complicate things too much

So demasiado means too much and goes before the object las cosas.

Compare:

• Habla demasiado. = He/She talks too much.
• Complica demasiado el problema. = He/She makes the problem too complicated.

If demasiado were directly describing a noun, it would change form when needed:

• demasiada paciencia
• demasiados libros
• demasiadas cosas

But in your sentence it is an adverb, so it stays demasiado.

Yes. Since la narradora is feminine singular, you could replace it with ella if the context is clear:

• Me gusta que ella explique el argumento con calma...

However, Spanish often prefers the noun instead of the subject pronoun when it helps clarity or emphasis. In many real contexts, la narradora sounds more natural because it reminds us exactly who is doing the explaining.

They can overlap, but they are not always exactly the same.

• el argumento usually means the plot or the storyline
• la historia can mean the story in a broader sense

So explicar el argumento often means explaining what happens in the narrative, especially the sequence or structure of events.

For a book, film, or series:

• argumento = the plot
• historia = the story as a whole

The word order is natural and standard:

• Me gusta que la narradora explique el argumento con calma y sin complicar demasiado las cosas.

Spanish could rearrange some parts for emphasis, but this version is the most neutral and straightforward.

The structure is:

• Me gusta = main clause
• que la narradora explique... = subordinate clause
• con calma y sin complicar demasiado las cosas = phrases describing how she explains it

So the sentence flows from:

1. the speaker’s reaction
2. the person acting
3. what she does
4. how she does it

Yes: it shows a very useful pattern:

• Me gusta que + subjunctive

This is used when you say you like someone else doing something.

Examples:

• Me gusta que me escuches. = I like that you listen to me.
• Me gusta que los alumnos participen. = I like the students participating / I like it when the students take part.
• Me gusta que todo esté claro. = I like everything to be clear.

A helpful contrast is:

• Me gusta explicar el argumento. = I like explaining the plot.
  
  • same subject implied: I like explaining
• Me gusta que la narradora explique el argumento. = I like that the narrator explains the plot.
  
  • different subject: the narrator does the explaining

That contrast is very important in Spanish.