Si tu veux te reposer, tu n’as qu’à éteindre ton téléphone.

In French, a real or likely condition is often built with:

• si + present
• followed by present, future, or imperative

Here we get:

• Si tu veux te reposer = if you want to rest
• tu n’as qu’à éteindre ton téléphone = you only have to / all you need to do is turn off your phone

So this is a normal, everyday conditional structure. It is not the same as the English pattern if + past, would + verb, which expresses something more hypothetical.

French normally repeats the subject pronoun in each clause.

So:

• Si tu veux te reposer
• tu n’as qu’à éteindre ton téléphone

Even though English might sometimes feel more flexible, French usually keeps the subject clearly stated. Leaving out the second tu would sound wrong here.

Se reposer is a pronominal/reflexive verb, meaning to rest or to get some rest.

Its full infinitive is:

• se reposer

When the subject is tu, se changes to te:

• tu veux te reposer

This does not always mean a literally reflexive action like wash yourself. In many French verbs, the reflexive form is just the normal way the verb is used.

Examples:

• je me repose
• tu te reposes
• il se repose

So te is there because the verb is se reposer, not just reposer.

After vouloir (to want), French uses an infinitive.

So the pattern is:

• vouloir + infinitive

Examples:

• Je veux dormir
• Tu veux manger
• Nous voulons partir

Because se reposer is the infinitive, it becomes te reposer after tu veux.

So:

• tu veux te reposer = correct

But:

• tu veux tu reposes = incorrect, because reposes is a conjugated form, not an infinitive

Ne... avoir qu’à + infinitive is a very common French expression meaning:

• you just have to...
• all you need to do is...

So:

• tu n’as qu’à éteindre ton téléphone

means something like:

• you just have to turn off your phone
• all you have to do is turn off your phone

This is not a literal only have to in the English sense; it is an idiomatic way to give a simple suggestion or solution.

Other examples:

• Tu n’as qu’à demander. = You just have to ask.
• On n’a qu’à attendre. = We just have to wait.

Yes, it is related.

Normally, ne...que means only:

• Je n’ai que deux euros. = I only have two euros.

In n’avoir qu’à + infinitive, that idea becomes part of a fixed expression:

• tu n’as qu’à + infinitive

The sense is:

• you only have to...
• therefore, it’s easy / that’s all you need to do

So grammatically it comes from ne...que, but in practice learners should remember n’avoir qu’à as a whole expression.

Because que is shortened before a word starting with a vowel sound.

Here:

• que + à becomes qu’à

French often drops the final e of words like que, je, ne, se before a vowel.

Other examples:

• je aime → j’aime
• ne as → n’as
• que il → qu’il

So n’as qu’à is just the normal contracted spelling.

Because after à in this expression, French uses the infinitive.

The pattern is:

• n’avoir qu’à + infinitive

So:

• tu n’as qu’à éteindre = correct

Not:

• tu n’as qu’à éteins = incorrect

The infinitive here is éteindre (to turn off).

Similar examples:

• Tu n’as qu’à attendre.
• Tu n’as qu’à essayer.

Ton is the informal singular possessive for your.

Because the sentence uses tu, the matching possessive is:

• ton (masculine singular noun)
• ta (feminine singular noun)
• tes (plural)

Since téléphone is masculine singular, French uses:

• ton téléphone

If the sentence used vous, it would be:

• votre téléphone

French often uses possessive adjectives where English might also use your, so this is very natural.

Yes, tu is informal singular.

This sentence is addressed to:

• a friend
• a family member
• a child
• someone you know well

With vous, it becomes more formal or plural:

• Si vous voulez vous reposer, vous n’avez qu’à éteindre votre téléphone.

Changes:

• tu veux → vous voulez
• te reposer → vous reposer
• tu n’as → vous n’avez
• ton téléphone → votre téléphone

Good question. In n’avoir qu’à, the structure contains ne...que, which is technically a negative-type construction in form, but its meaning here is idiomatic.

So although you see:

• n’... qu’...

the whole expression does not mean simple negation like you do not have to.

Instead, it means:

• you just have to
• all you need to do is

This is why learners should be careful not to interpret it word by word.

A careful pronunciation would be roughly:

• si tu veux te reposer, tu n’as qu’à éteindre ton téléphone
• /si ty vø tə ʁəpoze | ty na ka etɛ̃dʁə tɔ̃ telefɔn/

A few useful notes:

• tu sounds like ty, not like English too
• veux sounds like vø
• te in fast speech can sound very light, sometimes almost disappearing
• n’as qu’à is usually pronounced smoothly together
• ton has a nasal vowel, so the n is not pronounced like a full English n
• éteindre has a nasal sound in the middle: -tɛ̃-

In everyday spoken French, the ne is often dropped:

• Tu as qu’à éteindre ton téléphone

But in standard written French, tu n’as qu’à is preferred.

Yes. French can switch the order, just like English.

You can say:

• Si tu veux te reposer, tu n’as qu’à éteindre ton téléphone.
• Tu n’as qu’à éteindre ton téléphone si tu veux te reposer.

Both are correct.

The first version puts the condition first:

• If you want to rest...

The second version puts the suggestion first:

• You just have to turn off your phone...

The meaning stays basically the same, though the emphasis shifts a little.