Når jeg vil holde fokus på opgaven, sætter jeg min mobil på lydløs.

Når means when and introduces a subordinate clause.

In this sentence, Når jeg vil holde fokus på opgaven means When I want to keep my focus on the task.

A learner often notices that Danish uses når for situations that happen regularly or generally, not just one specific future event. So this sentence sounds like a habitual or general statement: whenever this situation happens, I put my phone on silent.

After the modal verb vil, Danish uses the infinitive without at.

So:

• jeg vil holde = I want to keep
• not jeg vil at holde

This is like other modal verbs in Danish:

• jeg kan gøre det = I can do it
• jeg skal gå = I must go
• jeg må vente = I may / must wait

So holde is in the infinitive, and vil is the conjugated verb.

In this sentence, vil means want to, not a simple future will.

Danish vil can sometimes look like English will, but very often it expresses desire, intention, or willingness. In this sentence, the meaning is clearly about intention:

• jeg vil holde fokus = I want to keep focus

If Danish wanted to emphasize a plain future meaning, context would usually make that clear.

Holde fokus is a natural Danish expression meaning keep focus or stay focused.

Here, fokus is used in a general sense, so it does not need a definite ending. Danish often leaves nouns indefinite in general expressions like this.

Compare:

• holde fokus = keep focus
• miste fokus = lose focus

You may also hear holde fokus på noget = keep focus on something.

På opgaven means on the task or on the assignment.

The preposition på is used with fokus here:

• fokus på noget = focus on something

And opgaven is the definite form of opgave:

• en opgave = a task / an assignment
• opgaven = the task / the assignment

So:

• holde fokus på opgaven = keep focus on the task

Because the speaker is referring to a specific task, not just any task.

• en opgave = a task
• opgaven = the task

In context, the person means the task they are working on, so Danish uses the definite form opgaven.

This is one of the most important Danish word-order patterns.

The sentence begins with a subordinate clause:

• Når jeg vil holde fokus på opgaven

After that comes the main clause. In Danish main clauses, the finite verb normally comes in second position. Because the sentence does not begin with the subject of the main clause, the verb comes before the subject:

• Når ..., sætter jeg ...

Not:

• Når ..., jeg sætter ...

This is the normal verb-second pattern in Danish.

Compare:

• Jeg sætter min mobil på lydløs.
• Når jeg arbejder, sætter jeg min mobil på lydløs.

In the second sentence, sætter still has to come early in the main clause.

Sætter is the present tense of sætte.

Danish present tense often ends in -r or -er, depending on the verb:

• at sætte = to put / to set
• jeg sætter = I put / I am putting

In this sentence, the present tense is used for a habitual action:

• When I want to focus on the task, I put my phone on silent.

So it is not necessarily happening right this second; it describes what the speaker generally does.

Yes. Mobil is a very common short form of mobiltelefon.

So:

• min mobil = my mobile phone / my phone

This is completely natural everyday Danish.

Also, min is the common possessive for a common-gender noun in the singular:

• en mobil
• min mobil

Yes, sætte noget på lydløs is a natural expression meaning put something on silent.

Literally:

• sætte = put / set
• på = on
• lydløs = silent / soundless

So:

• sætte mobilen på lydløs = put the phone on silent

This works very much like English put my phone on silent.

Here lydløs is used in a fixed phrase after på: på lydløs.

You can think of it almost as naming the phone setting: on silent.

Danish adjectives often change form depending on grammar, but in expressions like sætte noget på lydløs, the basic form lydløs is used idiomatically.

So learners usually do best to remember the whole chunk:

• at sætte noget på lydløs

Yes, in real life many Danes also say things like på lydløs or på stille, depending on the person and context.

However, på lydløs is completely natural and very easy to understand. It clearly means the phone is set so it does not make sounds.

For a learner, på lydløs is a very good expression to know.

It most naturally describes a usual or repeated action.

Two things suggest that:

• Når often introduces a general when(ever) idea
• the present tense in Danish often describes habits

So the sense is:

• Whenever I want to focus on the task, I put my phone on silent.

If the speaker wanted to describe one specific past event, Danish would use a different structure and tense.

Yes. A very useful breakdown is:

• Når = when
• jeg vil = I want to
• holde fokus = keep focus
• på opgaven = on the task
• sætter jeg = I put
• min mobil = my phone
• på lydløs = on silent

So the structure is:

• When I want to keep focus on the task, I put my phone on silent.

The main verbs are:

• at ville -> vil
• at holde -> holde
• at sætte -> sætter

So:

• vil is the present form of ville
• holde is an infinitive after the modal verb vil
• sætter is the present tense finite verb in the main clause

Seeing the base forms helps a lot when you learn Danish sentence structure.