Antes de guardar la tarjeta, mi amiga leyó la dedicatoria y sonrió.

Antes de is a fixed structure meaning before when it is followed by a noun or an infinitive.

So:

• antes de guardar la tarjeta = before putting away / saving the card

Spanish uses the infinitive after antes de when the action is general and does not need a separate subject stated. This is very common.

Compare:

• Antes de salir, cerré la puerta. = Before leaving, I closed the door.
• Antes de comer, me lavé las manos. = Before eating, I washed my hands.

If Spanish uses a full clause with a different subject, it often uses antes de que + subjunctive instead:

• Antes de que mi amiga guardara la tarjeta... = Before my friend put away the card...

In your sentence, antes de guardar la tarjeta is the shorter and more natural structure.

It can mean either, depending on context. Guardar has a broad meaning: to keep, save, put away, store, preserve.

In this sentence, with la tarjeta, the most natural idea is probably to put away the card or to keep the card. If the wider context is about a greeting card, birthday card, or handwritten card, guardar la tarjeta often means to keep it or put it away somewhere safe.

So guardar is one of those verbs whose exact English translation changes with context.

Mi amiga means my friend.

• mi = my
• amiga = female friend

You cannot say yo amiga because yo is a subject pronoun meaning I, not a possessive word. To show possession, Spanish uses mi, tu, su, nuestro, etc.

Could Spanish say just amiga? Not in this sentence if you mean my friend as the subject. You need the possessive:

• mi amiga = my friend

Also, amiga is feminine because the friend is female. If it were a male friend, it would be mi amigo.

Spanish often leaves out subject pronouns when the subject is clear from the verb form or from context.

Here, the sentence already says mi amiga, so adding ella would be unnecessary:

• Mi amiga leyó la dedicatoria y sonrió.

That is the normal, natural way.

You could say ella in some contexts, but usually only for emphasis, contrast, or clarification:

• Mi amiga leyó la dedicatoria y ella sonrió, pero yo no.

In ordinary sentences, Spanish avoids repeating the subject when it is already obvious.

Leyó is the preterite form of leer for él/ella/usted: he/she read.

The verb leer has an irregular spelling change in some preterite forms to keep pronunciation natural:

• leí
• leíste
• leyó
• leímos
• leísteis
• leyeron

The y appears in forms like leyó and leyeron because Spanish does not use forms like leió.

So:

• mi amiga leyó = my friend read

The accent on ó is also important because it shows stress and helps distinguish the form correctly.

The accent in leyó marks the stressed syllable and is part of the correct spelling of the preterite form.

Without the accent, leyo would be pronounced differently and would not be the standard written form for this verb tense.

This is common in many preterite third-person singular forms:

• habló
• comió
• vivió
• leyó
• sonrió

So the accent is not optional; it is required.

La dedicatoria means the dedication, usually a written message addressed to someone.

In the context of a card, it often refers to the handwritten message inside, such as:

• a loving message
• a birthday note
• a personal inscription

So it is not the card itself, but the message written in or on it.

It is feminine, which is why it uses la:

• la dedicatoria

Because leer is a direct transitive verb: you read something.

So:

• leyó la dedicatoria = she read the dedication

The dedication is the direct object, so no a is used.

Spanish uses the personal a with specific people, and sometimes personified beings, when they are direct objects:

• Vi a mi amiga. = I saw my friend.

But with things, such as la dedicatoria, no personal a is used:

• Leí la dedicatoria.
• Guardó la tarjeta.

Sonrió is the preterite of sonreír, meaning to smile.

Here:

• sonrió = she smiled

Like leer, sonreír has a spelling pattern in the preterite that can look unusual to learners. Some key forms are:

• sonreí
• sonreíste
• sonrió
• sonreímos
• sonreísteis
• sonrieron

So the sentence gives two completed past actions:

• she read the dedication
• she smiled

They are in the preterite because the sentence describes completed actions in the past.

• leyó = she read
• sonrió = she smiled

The preterite is used for actions seen as finished events. In this sentence, the sequence is clear:

1. before putting away the card
2. my friend read the dedication
3. and smiled

These are presented as single, completed actions, not ongoing background actions. That is why the preterite is the natural tense here.

If the sentence were describing ongoing background or habitual actions, the imperfect might be used instead, but that would change the meaning.

The comma separates the introductory phrase from the main clause:

• Antes de guardar la tarjeta, = introductory time expression
• mi amiga leyó la dedicatoria y sonrió. = main clause

In English, we often do the same thing:

• Before putting away the card, my friend read the dedication and smiled.

In Spanish, this comma is very natural and helps readability.

Because y simply links the two verbs that share the same subject:

• mi amiga leyó la dedicatoria y sonrió

That means:

• my friend read the dedication and smiled

Spanish does not need to repeat the subject:

• mi amiga leyó la dedicatoria y mi amiga sonrió

That version is grammatical, but it sounds repetitive unless you want special emphasis.

So one y is enough to connect the two completed actions.

Yes, Spanish is more flexible than English with word order, although some versions sound more natural than others.

For example, you could say:

• Mi amiga leyó la dedicatoria y sonrió antes de guardar la tarjeta.

This puts the before phrase at the end instead of the beginning. The meaning stays essentially the same.

The version you were given starts with Antes de guardar la tarjeta to set the time frame first. That is a very common and natural way to structure a sentence in Spanish.

Tarjeta can mean several kinds of card, depending on context:

• greeting card
• bank card
• business card
• ID card
• note card

Because the sentence includes la dedicatoria, the most likely meaning is a greeting card or some kind of card with a written message inside.

So the wider context helps determine exactly which kind of card is meant.

Yes. The sentence is fully natural and correct in Spanish from Spain.

It has several very normal features of everyday Spanish:

• antes de + infinitive
• omission of unnecessary subject pronouns
• preterite for completed past actions
• two actions linked with y

It sounds a bit more polished than very casual conversation because of the word dedicatoria, but it is still completely normal and idiomatic.