Vi må få ryddet kjøkkenbenken før gjestene kommer i kveld.

In Norwegian, må is a modal verb that primarily means must / have to (necessity or strong obligation), as in Vi må ... = We have to ....
It does not mean may (permission). For permission, Norwegian typically uses kan (Can I...?) or får (Am I allowed to...?), depending on context.

få + past participle is a common Norwegian construction meaning something like:

• have (something) done
• manage to get (something) done
• make sure (something) gets done

So Vi må få ryddet kjøkkenbenken implies: We need to ensure the kitchen counter gets cleared/tidied (before the guests arrive). It can sound a bit more goal-focused than Vi må rydde kjøkkenbenken, which is simply We have to tidy the kitchen counter.

Because this construction uses past participle after få:

• infinitive: å rydde (to tidy)
• past participle: ryddet (tidied)

So få ryddet is literally “get [it] tidied,” i.e. “get it done / get it cleared.”

It can be either, depending on context. Vi må få ryddet ... focuses on the result (that it becomes tidy), not strictly on who does it.

• If you’re talking at home with family, it usually implies we’ll do it ourselves.
• In other contexts, it could imply arranging for someone else to do it (e.g., hiring help), but context normally makes that clear.

kjøkkenbenken means the kitchen counter / the kitchen worktop. Norwegian often forms compounds as a single word:

• kjøkken (kitchen) + benk (bench/counter) → kjøkkenbenk

Then the definite ending is added:

• en kjøkkenbenk = a kitchen counter
• kjøkkenbenken = the kitchen counter

Norwegian commonly uses the definite form when referring to a specific, known thing in the situation—here, the counter everyone knows about (the one in your kitchen). English often allows the or sometimes a more general phrasing, but Norwegian naturally prefers the definite form in everyday situations like this.

• en gjest = a guest
• gjester = guests (indefinite plural)
• gjestene = the guests (definite plural)

Here it’s specific guests that both speaker and listener have in mind, so Norwegian uses the definite plural: gjestene.

Norwegian often uses present tense in time clauses about the future, especially after conjunctions like før (before), når (when), etter at (after):

• før gjestene kommer = before the guests arrive (later today)

English also sometimes does this (before the guests arrive), but Norwegian does it very consistently.

Yes, a typical difference is:

• kommer i kveld: neutral, natural “they’re coming tonight” (often sounds like a planned/expected event)
• skal komme i kveld: more explicitly about plan/intention/arrangement (“they’re going to come tonight”)

In many everyday contexts, kommer i kveld is the most idiomatic.

The sentence is structured as: 1) main clause: Vi må få ryddet kjøkkenbenken
2) time clause: før gjestene kommer i kveld

Placing the før-clause at the end is very common: you state what must be done first, then add the deadline/condition. You can also front the time clause, but then Norwegian word order changes (verb-second rule):

• Før gjestene kommer i kveld, må vi få ryddet kjøkkenbenken.
  Notice må comes before vi in the main clause because the clause starts with something other than the subject.