Alzamos los pliegos para formar un cuadernillo.

It can be either, because alzamos has the same form in:

• present indicative: we raise / we lift
• preterite: we raised / we lifted

So the sentence is grammatically ambiguous by itself. In context, it is often understood as the present if someone is describing a process or giving step-by-step information, but it could also be past if the surrounding text is telling what happened.

Spanish often drops subject pronouns because the verb ending already shows who the subject is.

• alzamos = we lift / we raise / we gathered
• so nosotros is not necessary

You could say Nosotros alzamos los pliegos..., but that usually adds emphasis, contrast, or clarity. In normal Spanish, leaving it out is more natural.

In general Spanish, alzar often means to raise, to lift, or to pick up.

But in a printing or bookbinding context, it can have a more technical meaning, closer to:

• to gather
• to collate
• to assemble sheets in order

So this is probably not just a physical lifting movement. It is likely a specialized action involving sheets used to make a booklet or section.

Pliegos is the plural of pliego.

In everyday Spanish, pliego can mean a sheet or large piece of paper. In printing and bookbinding, it is more technical and usually refers to a printed sheet that may later be folded and assembled.

So los pliegos here refers to the specific sheets being used in the process.

This is about the articles:

• los pliegos = the sheets
  These are specific sheets already known in the context.
• un cuadernillo = a booklet / a section / a gathering
  This introduces the result as one item, not previously identified.

So the sentence treats the sheets as known materials, and the cuadernillo as the thing being formed.

Para + infinitive expresses purpose.

So:

• para formar un cuadernillo = in order to form a booklet / section

This structure is very common in Spanish when the subject of both actions is the same:

• Alzamos los pliegos
• para formar un cuadernillo

The same we is understood for both actions.

Because para + infinitive is normally used when the subject is the same in both parts of the sentence.

Here, the implied subject is we in both actions:

• we gather/lift the sheets
• we form a booklet/section

If the subject changed, Spanish would normally use para que + subjunctive.

For example:

• Alzamos los pliegos para que el encuadernador forme el cuadernillo.

Here, we do the first action, but the bookbinder does the second one, so para que + forme is needed.

Grammatically, cuadernillo is built from cuaderno with the diminutive ending -illo, so literally it can suggest something like a small notebook.

But in printing and bookbinding, cuadernillo is often a technical term. It usually refers to:

• a booklet
• a section
• a gathering / signature of folded sheets

So although it looks like a simple diminutive, in this context it is probably best understood as specialized vocabulary, not just little notebook.

Yes, formar is very natural here because it suggests creating something by arranging parts into a structure.

That fits this context well:

• sheets are being assembled
• the result is a cuadernillo

Hacer is more general and would be less precise. Formar sounds more appropriate for a process where parts are organized into a whole.

Yes. Spanish word order is fairly flexible, especially when the meaning is clear.

For example, these are possible:

• Alzamos los pliegos para formar un cuadernillo.
• Para formar un cuadernillo, alzamos los pliegos.

The original order is very natural:
verb + object + purpose

Changing the order can shift the emphasis. Starting with para formar un cuadernillo puts more focus on the purpose.

Yes, it sounds fairly technical or specialized, especially because of:

• pliegos
• cuadernillo
• possibly alzar, depending on the exact trade meaning

A native speaker would likely associate this with:

• printing
• publishing
• bookbinding
• paper handling

So even if the grammar is straightforward, the vocabulary is not especially everyday.

Sometimes in general Spanish, alzar and levantar can overlap because both can mean to lift / raise.

However, in a technical context, alzar may be the preferred verb if it refers to a specific operation in printing or bookbinding. Replacing it with levantamos might sound:

• less precise
• less technical
• more physical and literal

So although levantamos might make sense in plain language, alzamos is probably chosen for a reason here.

In standard Peninsular Spanish, it is pronounced approximately:

• kwa-der-NEE-yo

A few useful points:

• the stress is on -ni-: cuaderNILlo
• ll in most of Spain is pronounced like y
• cue- starts with a kw sound: cua-

So the important stress pattern is:

• cua-der-NI-llo

It is:

• Verb: Alzamos
• Direct object: los pliegos
• Purpose phrase: para formar un cuadernillo

So structurally, it is:

[We] + verb + thing affected + purpose

That makes it a very useful model for other sentences, such as:

• Cortamos el papel para hacer tarjetas.
• Doblamos las hojas para crear un folleto.

The pattern is common and worth remembering.