Jeg vil fortælle mere om min rejse, når jeg har øvet mig på mit nye klaverstykke.

Vil + infinitive is a very common way to talk about what someone wants to do or is going to do.

So jeg vil fortælle can mean:

• I want to tell
• or, depending on context, I will tell / I’m going to tell

In this sentence, it sounds natural because the speaker is talking about something they plan to do later.

A plain present tense, jeg fortæller, would usually mean I tell / I am telling, and would not fit this future-looking idea as well.

The verb fortælle means to tell. Very often in Danish, if you say what topic you are telling about, you use om:

• fortælle om noget = tell about something
• fortælle mere om noget = tell more about something

So:

• Jeg vil fortælle mere om min rejse = I want to tell more about my trip/journey

This is very similar to English tell more about.

Because rejse is a common gender noun in Danish.

Danish nouns are mainly either:

• common gender → use en, min
• neuter → use et, mit

So:

• en rejse
• min rejse

Compare:

• et hus → mit hus

A good habit is to learn nouns together with their article:

• en rejse
• et klaverstykke

Når is used for something that happens when/whenever a situation is true, especially in the present or future.

In this sentence, the speaker means:

• when I have practiced my new piano piece

That is a future condition, so når is the natural choice.

A useful contrast:

• når = when, for repeated events or future situations
• da = when, for a specific event in the past

So:

• Når jeg kommer hjem, ringer jeg = When I get home, I’ll call
• Da jeg kom hjem, ringede jeg = When I got home, I called

Danish often uses the present perfect here: har øvet mig.

This points to an action being completed before the next action happens:

• first: I practice
• then: I tell more about my trip

So når jeg har øvet mig is literally like:

• when I have practiced

In natural English, we often simplify this to:

• when I’ve practiced
• or even after I practice

The Danish form emphasizes that the practicing will be done before the telling happens.

The verb here is øve sig, which is a reflexive verb in Danish.

That means it often takes a reflexive pronoun:

• jeg øver mig
• du øver dig
• han/hun øver sig
• vi øver os

So jeg har øvet mig means I have practiced.

This is different from English, where we usually just say practice without a reflexive pronoun.

You can think of øve sig as the standard way to say that a person is practicing.

With øve sig, Danish often uses på to introduce the thing you are practicing:

• øve sig på noget = practice something / practice on something

So:

• jeg øver mig på stykket = I’m practicing the piece

This is just the normal Danish pattern. English does not always need a preposition here, but Danish often does.

Because klaverstykke is a neuter noun:

• et klaverstykke

Neuter nouns usually take:

• mit for my
• adjective ending -t in the indefinite singular, if there is no other ending already

However, here the adjective is ny → nyt in neuter, but because of sound changes and normal spelling, the phrase becomes:

• mit nye klaverstykke

Why nye and not nyt?
Because when an adjective comes after a possessive like mit, Danish usually uses the weak form:

• min nye bog
• mit nye klaverstykke

So the full phrase is:

• mit because the noun is neuter
• nye because the adjective follows a possessive
• klaverstykke because that is the noun

Klaverstykke is a compound noun:

• klaver = piano
• stykke = piece

Together:

• klaverstykke = piano piece

Danish forms compound nouns very freely, and they are usually written as one word. This is very common and important in Danish.

Other examples:

• togstation = train station
• sommerferie = summer holiday
• arbejdsdag = workday

In a subordinate clause introduced by a word like når, Danish normally keeps the subject before the finite verb:

• når jeg har øvet mig

Structure:

• når = subordinating conjunction
• jeg = subject
• har = finite verb
• øvet mig = rest of the verb phrase

So this is standard subordinate-clause word order.

Compare:

• main clause: Jeg har øvet mig
• subordinate clause: når jeg har øvet mig

The comma marks the beginning of the subordinate clause:

• main clause: Jeg vil fortælle mere om min rejse
• subordinate clause: når jeg har øvet mig på mit nye klaverstykke

In Danish, many writers put a comma before subordinate clauses like this. You may also hear about start comma rules in Danish, because comma practice has changed over time. So whether you always see this comma can depend a little on the system being followed.

But in a sentence like this, the comma helps show the structure clearly.

Yes. Danish can also put the time clause first:

• Når jeg har øvet mig på mit nye klaverstykke, vil jeg fortælle mere om min rejse.

That is also completely natural.

Notice what changes in the main clause:

• Jeg vil fortælle ... becomes
• vil jeg fortælle ...

This is because Danish is a V2 language: in a main clause, the finite verb usually comes in the second position. When the når-clause comes first, it counts as the first element, so vil comes before jeg.

Both can often be translated as trip or journey, but they are not always used in exactly the same way.

Very roughly:

• rejse often emphasizes the fact of traveling, a journey, or a trip as a larger event
• tur is extremely common for an outing, trip, ride, or turn

In this sentence, min rejse sounds natural because the speaker is talking about their journey/trip as something they can tell more about.

So even if English might sometimes use trip, journey, or travel, Danish rejse fits well here.