La audioguía y la ficha técnica explican la acuarela sobre lienzo.

Because audioguía is a feminine noun, so it takes la.

A common rule learners hear is that some feminine nouns beginning with a stressed a- sound use el in the singular, like el agua. But that does not apply here, because audioguía does not begin with a simple stressed a sound. It begins with the diphthong au-, and the stress falls later: au-dio-guí-a.

So the correct form is la audioguía.

Because the subject is plural: La audioguía y la ficha técnica.

Spanish, like English, makes the verb agree with the subject. Since there are two things joined by y (and), the subject is plural, so the verb must also be plural:

• la audioguía = singular
• la ficha técnica = singular
• la audioguía y la ficha técnica = plural
• therefore: explican = they explain

In this context, ficha técnica is the museum or gallery information card/listing that gives the technical details of the artwork.

It often includes things like:

• the artist
• title
• date
• materials
• dimensions
• collection or location

So it is not usually technical sheet in a mechanical sense. In an art setting, it is more like an information label, catalog entry, or technical description card.

It is an art-description phrase.

• acuarela = watercolor
• sobre = on
• lienzo = canvas

So acuarela sobre lienzo means watercolor on canvas.

In museum language, this describes the medium/support of the work. Spanish often uses this structure:

• óleo sobre lienzo = oil on canvas
• tinta sobre papel = ink on paper
• acuarela sobre papel = watercolor on paper

Here, la acuarela sobre lienzo refers to the watercolor-on-canvas work.

Because acuarela is feminine singular, and here it refers to a specific artwork.

Spanish uses definite articles more often than English. In this sentence, la acuarela sobre lienzo is understood as a particular piece being discussed, so Spanish naturally uses la.

Even when English might say something like the watercolor painting or just the work, Spanish often keeps the article:

• la acuarela
• la obra
• el cuadro

Because explicar is normally a direct-object verb in Spanish. You explain something:

• explicar algo
• explicar la lección
• explicar el problema
• explicar la acuarela sobre lienzo

English sometimes uses slightly different patterns, but in Spanish you usually do not say explican sobre la acuarela when you mean they explain the watercolor painting.

So in this sentence:

• La audioguía y la ficha técnica = subject
• explican = verb
• la acuarela sobre lienzo = direct object

Here, sobre means on, not about.

Spanish sobre can have different meanings depending on context:

• el libro está sobre la mesa = the book is on the table
• un texto sobre arte = a text about art
• acuarela sobre lienzo = watercolor on canvas

In this sentence, it is part of the art-material description, so sobre lienzo means on canvas.

Because Spanish generally uses definite articles more often than English, especially with known objects, categories, and items in a specific context.

Here, all three nouns are presented as identifiable things in a museum setting:

• la audioguía
• la ficha técnica
• la acuarela sobre lienzo

English might sometimes omit an article in a similar situation, but Spanish usually keeps it.

The sentence follows a very common Spanish pattern:

Subject + verb + direct object

So here we have:

• La audioguía y la ficha técnica = subject
• explican = verb
• la acuarela sobre lienzo = direct object

This is straightforward and natural Spanish word order.

The accent marks show the stressed syllable and help follow Spanish spelling rules.

• audioguía: the accent marks the stress on guí
• técnica: the accent marks the stress on téc

Without going too deep into the spelling rules, the accents help indicate the correct pronunciation:

• au-dio-GUÍ-a
• TÉC-ni-ca

For learners, it is best to memorize both the spelling and the stress together.

It can suggest both, but in this sentence it most naturally refers to the artwork, described by its medium and support.

So la acuarela sobre lienzo means something like:

• the watercolor-on-canvas painting
• the watercolor on canvas work

Spanish often names an artwork by its medium:

• el óleo
• la acuarela
• el grabado

So here, the phrase identifies the piece through what it is made with and what it is made on.