La plegadera está junto a la guillotina.

Because the sentence is talking about location: where something is.

In Spanish, estar is normally used for location:

• La plegadera está junto a la guillotina. = The folder/bone folder is next to the guillotine.

Ser is used for identity, definition, origin, and other more permanent descriptions:

• La plegadera es una herramienta. = The folder is a tool.

So here, está is the correct choice because it tells you where the object is.

The accent mark is important because está and esta are different words.

• está = is / it is / he is / she is from estar
• esta = this (feminine), as in esta máquina = this machine

The accent shows both the correct pronunciation and that it is the verb form, not the demonstrative word.

Both plegadera and guillotina are feminine singular nouns, so they take the feminine singular article la.

• la plegadera
• la guillotina

In this sentence, la also shows that we are talking about specific objects, not just any object of that type.

Spanish usually keeps the article in places where English might or might not use the. So:

• La plegadera está junto a la guillotina is natural.
• Leaving out the articles would sound wrong here.

Usually, nouns ending in -a are often feminine, and that is true for these two words:

• la plegadera
• la guillotina

But this is only a general pattern, not a guaranteed rule. The safest way is to learn nouns together with their article:

• la plegadera
• la guillotina

That helps you remember gender correctly from the start.

Junto a means next to, beside, or right by.

It expresses close physical position:

• La plegadera está junto a la guillotina. = The folder is next to the guillotine.

It is very similar to:

• al lado de = next to / at the side of

Sometimes junto a can sound a little more formal or written than al lado de, but both are common and correct.

Because the normal fixed expression is junto a.

In this sentence, junto a works as a prepositional expression meaning next to:

• junto a la guillotina

So you should learn it as one unit:

• junto a + noun
• junto al
  • masculine singular noun beginning with el
• junto a la
  • feminine singular noun

Examples:

• junto al libro
• junto a la mesa

Because here junto is not acting like a normal adjective that agrees with plegadera. It is part of the expression junto a, which functions like next to.

So it stays:

• La plegadera está junto a la guillotina.
• El libro está junto a la caja.

No agreement change happens there.

Compare that with real adjective use, where agreement does happen:

• Las dos máquinas están juntas. = The two machines are together.

In that case, juntas is an adjective and changes form.

Yes, but the original order is the most neutral and straightforward:

• La plegadera está junto a la guillotina.

You can also move the location phrase first for emphasis or style:

• Junto a la guillotina está la plegadera.

That version is grammatical, but it sounds a bit more marked or literary. For everyday learning, the original word order is the best one to use first:

• subject + verb + place

A good approximate pronunciation is:

gee-yo-TEE-na

A few useful points:

• gui: the u is silent here, so it sounds like gi
• ll in most of Spain is pronounced similarly to English y in yes
• the stress falls on -ti-: gui-llo-TI-na

And está is stressed on the last syllable:

• es-TÁ

So the whole sentence is roughly: la ple-ga-DE-ra es-TÁ HUN-to a la gee-yo-TEE-na

In much of Spain, j in junto has a strong throaty sound, not an English j sound.

Yes. That is a very common alternative.

• La plegadera está junto a la guillotina.
• La plegadera está al lado de la guillotina.

Both mean essentially the same thing: The folder is next to the guillotine.

A learner will hear al lado de very often in everyday speech, while junto a is also completely normal and often a bit more compact.