Guardamos las cajas en el trastero del sótano para que el salón quede libre.

Here guardamos means we store / we put away / we keep.

Spanish guardar often means more than just to guard. In everyday use, it commonly means to put something away in its proper place, especially for storage.

So:

• Guardamos las cajas = We put the boxes away / We store the boxes
• Ponemos las cajas would only mean we put the boxes somewhere, without the same idea of storing them neatly or out of the way.

In this sentence, guardar fits better because the point is that the boxes are being kept in storage so the living room stays free.

Guardamos is the first person plural form of guardar, so it means we store / we are storing / we stored, depending on context.

The ending -amos tells you it matches nosotros / nosotras = we.

Examples:

• Guardo = I store
• Guardas = you store
• Guarda = he/she stores
• Guardamos = we store
• Guardáis = you all store (Spain)
• Guardan = they / you all store

Since the sentence is talking about we, guardamos is the correct form.

Formally, guardamos can be either:

• present indicative: we store / we are storing
• preterite for -ar verbs: we stored

That’s because the nosotros form looks the same in both tenses for regular -ar verbs.

So the meaning depends on context:

• Hoy guardamos las cajas... = Today we’re putting the boxes away...
• Ayer guardamos las cajas... = Yesterday we put the boxes away...

If this sentence is being given on its own, many learners will naturally read it as a present-time statement: We put/store the boxes in the basement storage room so that the living room stays free.

Because Spanish often drops subject pronouns when they are not needed.

The verb ending already tells you who the subject is:

• guardamos already means we store

So Nosotros guardamos las cajas... is possible, but nosotros is usually unnecessary unless you want emphasis, contrast, or clarity.

For example:

• Guardamos las cajas... = normal, natural
• Nosotros guardamos las cajas, no ellos. = We store the boxes, not them

This is one of the big differences from English, where you usually have to say we.

In Spain, trastero usually means a storage room, storage unit, or small room for keeping things.

It’s very common in Spain, especially in apartment buildings, where people may have a separate storage space in the basement or garage area.

So el trastero del sótano means something like:

• the storage room in the basement
• the basement storage room

A native English speaker might be tempted to translate it literally as junk room, but that sounds odd in English. Storage room is the most natural translation.

Del sótano means of the basement or more naturally in English in the basement.

So:

• el trastero = the storage room
• el trastero del sótano = the storage room in the basement / the basement storage room

This adds extra information, specifying which storage room.

Grammatically, del is a contraction of:

• de + el = del

So:

• del sótano = of the basement

In English, we often translate this more naturally as in the basement rather than of the basement.

Spanish often uses the definite article more than English does.

Here las cajas means the boxes. It refers to specific boxes that both speaker and listener already know about, or that are understood from context.

So:

• Guardamos las cajas... = We put the boxes away...

If you said Guardamos cajas, it would sound more general, like:

• We store boxes
• We put away boxes in general

In this sentence, the article makes it sound like we’re talking about particular boxes.

Use para que when it means so that and is followed by a new verb with its own subject or result clause.

Here:

• para que el salón quede libre = so that the living room stays/remains free

This structure is very common:

• para que + subjunctive

By contrast, plain para is used before an infinitive:

• Guardamos las cajas para dejar libre el salón. = We put the boxes away to leave the living room free.

Both are possible, but they are structured differently:

• para que + finite verb: para que el salón quede libre
• para + infinitive: para dejar libre el salón

Because after para que, Spanish normally uses the subjunctive, not the indicative.

So:

• para que el salón quede libre = correct
• para que el salón queda libre = incorrect

Quede is the present subjunctive of quedar.

This happens because para que introduces a purpose: the action is done so that something happens.

Some other examples:

• Te llamo para que vengas. = I’m calling you so that you come.
• Cierra la puerta para que no entre frío. = Close the door so that no cold air comes in.

So in your sentence, quede is there because the speaker is expressing the intended result or purpose.

Quedar often means to remain, to end up, or to be left in a certain state.

So:

• quedar libre = to remain free / to be left clear / to stay empty and available

In this sentence:

• para que el salón quede libre

means the living room is left uncluttered, clear, or available for use.

It does not necessarily mean completely empty. It means there is space and the room isn’t being taken up by the boxes.

Sometimes, but free / clear is usually better here.

Libre suggests:

• not occupied
• not blocked
• available
• clear of clutter

If you said vacío, that would mean more literally empty.

Compare:

• El salón queda libre = the living room remains free/clear
• El salón queda vacío = the living room remains empty

In your sentence, libre is better because the idea is that the boxes are removed so the room can be used comfortably.

Yes. Spanish word order is often more flexible than English word order, as long as the meaning stays clear.

The original sentence:

• Guardamos las cajas en el trastero del sótano para que el salón quede libre.

You could also say:

• En el trastero del sótano guardamos las cajas para que el salón quede libre.
• Para que el salón quede libre, guardamos las cajas en el trastero del sótano.

These versions change the emphasis:

• starting with En el trastero... emphasizes the place
• starting with Para que... emphasizes the purpose

The original order is very natural and neutral.

Yes. A few natural alternatives are:

• Guardamos las cajas en el trastero del sótano para dejar libre el salón.
• Metemos las cajas en el trastero del sótano para que el salón quede libre.
• Dejamos las cajas en el trastero del sótano para que el salón quede despejado.

Nuances:

• guardar = put away/store
• meter = put in
• dejar libre = leave free
• despejado = clear, uncluttered

Your original sentence is very natural, especially in Spain.

Yes, trastero is especially common in Spain.

In other Spanish-speaking regions, people might use different words depending on the country, such as:

• depósito
• bodega
• cuarto de trastos
• cuarto de almacenamiento

That said, learners of Spain Spanish should definitely know trastero, because it is very common there.