La regla és a les instruccions.

Because regla is a feminine singular noun in Catalan.

• la = the, for feminine singular nouns
• regla = rule

So:

• la regla = the rule

If the noun were masculine, you would use el instead.

Not always. Regla can mean different things depending on context, including rule and sometimes ruler.

In this sentence, the meaning is determined by the context you were given. So even though the word can have more than one meaning, here you should understand it as the intended one from the translation.

This is normal in Catalan, just as in English many words have more than one meaning.

És with an accent is the verb form meaning is.

• és = is
• es without an accent is usually a pronoun, like himself / herself / itself / oneself in certain structures

So the accent is important because it changes the word completely.

In this sentence:

• La regla és... = The rule is...

És is the 3rd person singular of ser, which usually means to be.

A learner may expect estar for location, and that is a good question. In Catalan, ser and estar do not match English to be perfectly.

With location, usage can vary by context and variety of Catalan. In sentences like this, ser can be used to indicate where something is found or located. Many speakers might also say La regla està a les instruccions, especially if they are thinking of physical or specific location.

So the important thing is:

• és here is acceptable Catalan
• està may also sound natural in many contexts, depending on the speaker and nuance

Because Catalan a often covers meanings that English separates into to, at, in, and sometimes on, depending on context.

So:

• a les instruccions literally looks like to the instructions
• but in natural English it means in the instructions

This is very common when talking about places, sections of text, pages, lists, instructions, and similar contexts.

So you should not translate a word-for-word every time. Translate the whole phrase naturally.

Because a only contracts with some definite articles in Catalan.

Common contractions:

• a + el = al
• a + els = als

But with feminine articles, there is no contraction:

• a + la = a la
• a + les = a les

So a les instruccions is exactly what you should expect.

Because instruccions is plural feminine.

• singular: la instrucció = the instruction
• plural: les instruccions = the instructions

The article has to agree with the noun:

• la for feminine singular
• les for feminine plural

No, this is a normal Catalan sentence order:

• La regla = subject
• és = verb
• a les instruccions = location/complement

So it follows a straightforward pattern similar to English:

• The rule is in the instructions

Catalan can change word order for emphasis, but this version is neutral and standard.

In many contexts, yes, many speakers would say that, and it can sound very natural.

The difference is subtle and depends on dialect and how the speaker sees the situation:

• és can present where something is found
• està often emphasizes actual location or position

For a learner, the safest takeaway is that és in your sentence is not a mistake, even if you may also encounter està in similar sentences.

A simple learner-friendly pronunciation guide would be:

lah REH-glah es ah lez in-strook-see-ONS

A few helpful points:

• regla has the stress on the first syllable: REH-gla
• és sounds like es with a clear e
• les is usually pronounced with a z-like sound before a vowel in connected speech
• instruccions has the stress near the end: -ons

Exact pronunciation varies a bit by dialect, but this will get you close.