Hun skal opptre på scenen.

Because skal is a modal verb in Norwegian, and modal verbs are normally followed by the bare infinitive — that is, the infinitive without å.

So:

• Hun skal opptre = She is going to perform

Compare:

• Hun liker å opptre = She likes to perform
• Hun vil opptre = She wants/will perform

After verbs like skal, vil, kan, må, and bør, you usually do not use å before the next verb.

In this sentence, skal means something like is going to, will, or is supposed to, depending on context.

So Hun skal opptre på scenen can suggest:

• a future plan: She is going to perform on stage
• an arranged event: She will perform on stage
• sometimes an obligation or expectation: She is supposed to perform on stage

Norwegian skal often covers both future and obligation/expectation, so the exact meaning depends on the situation.

Opptre usually means to perform, to appear, or sometimes to behave, depending on context.

In this sentence, because of på scenen (on the stage), it clearly means to perform.

Examples:

• Hun opptrer i kveld. = She is performing tonight.
• Bandet skal opptre på festivalen. = The band is going to perform at the festival.

In other contexts, it can also mean behave:

• Han opptrer høflig. = He behaves politely.

So it is a verb with more than one possible meaning.

Because scenen is the definite form of scene.

• en scene = a stage
• scenen = the stage

Norwegian often uses the definite form where English might also use the:

• på scenen = on the stage

The definite article is usually attached to the end of the noun as a suffix:

• en bil → bilen
• en scene → scenen

Hun is the subject pronoun meaning she.

This sentence follows normal Norwegian word order for a main clause:

Subject + verb + infinitive + adverbial/place

So:

• Hun = subject
• skal = finite verb
• opptre = main verb
• på scenen = place expression

This is the standard, neutral way to build the sentence.

Yes. That is also natural Norwegian.

• Hun skal opptre på scenen
• Hun kommer til å opptre på scenen

Both can mean She is going to perform on stage, but they are not always identical in tone.

Very roughly:

• skal often sounds like a plan, arrangement, or expectation
• kommer til å often sounds like a future event or prediction

In many everyday situations, both are possible.

In a yes/no question, the finite verb usually comes first:

• Skal hun opptre på scenen? = Is she going to perform on stage?

This is a common Norwegian pattern:

• statement: Hun skal opptre på scenen.
• question: Skal hun opptre på scenen?

So the verb skal moves in front of the subject hun.

If you move that part to the front, Norwegian uses verb-second word order:

• På scenen skal hun opptre.

This still means the same thing, but now på scenen is being emphasized.

Notice that when something other than the subject comes first, the finite verb skal must still stay in the second position:

• På scenen
  • skal
    • hun
      • opptre

This is a very important Norwegian word-order rule.

Not in the same way as some German verbs. In dictionaries, the verb is written as opptre.

Its forms include:

• infinitive: opptre
• present: opptrer
• past: opptrådte
• past participle: opptrådt

So you should learn it as one verb: å opptre.

A careful approximation is:

hun skal OPP-tre po SHAY-nen

A few useful notes:

• hun is often pronounced with a rounded vowel somewhat like hoon, but shorter
• skal has a broad a
• opptre has stress on the first syllable: OPP-tre
• på has an å sound, roughly like po in many teaching approximations
• scenen is often pronounced with sj-sound at the start: SHE-nen or SHAY-nen, depending on accent

Exact pronunciation varies a bit by dialect, but this should help you recognize it.

Yes. In many contexts, Norwegian på scenen can correspond to either:

• on stage
• on the stage

English sometimes prefers on stage as a more idiomatic expression for performing, while Norwegian naturally uses på scenen.

So even if the literal form looks like on the stage, the natural meaning may simply be on stage.