Efter festen samler vi pant i køkkenet.

Because festen is the definite form of fest: fest = party, festen = the party.

In Danish, definiteness is often added as an ending:

• en fest = a party
• festen = the party

So Efter festen means after the party, referring to a specific party.

This is because Danish follows the V2 rule in main clauses: the finite verb normally comes in second position.

Here, Efter festen has been placed first:

• Efter festen | samler | vi pant i køkkenet.

So once Efter festen takes the first slot, the verb samler must come next, and the subject vi comes after that.

Compare:

• Vi samler pant i køkkenet efter festen.
• Efter festen samler vi pant i køkkenet.

Both are correct, but the word order changes because of the V2 rule.

Pant is a very common Danish word that refers to the deposit value on bottles and cans, and by extension the returnable bottles/cans themselves.

So in everyday Danish, samle pant means something like:

• collecting deposit bottles and cans
• gathering recyclables that can be returned for money

Even if the English meaning has already been given, it is useful to know that pant is a very culturally common word in Denmark because of the bottle/can refund system.

Because pant is often treated as a mass noun or collective noun in this context.

Danish often says:

• samle pant
• aflevere pant
• der ligger pant på bordet

This works much like English collect recycling or collect trash, where you do not necessarily need a or the.

If you wanted to be more specific, you could use other nouns:

• flaskerne = the bottles
• dåserne = the cans

But pant is a natural general word for the category.

Because i usually means in and is used for being inside a room or enclosed space.

So:

• i køkkenet = in the kitchen
• i stuen = in the living room
• i soveværelset = in the bedroom

På is used in other kinds of locations, such as surfaces or certain institutions/places:

• på bordet = on the table
• på skolen = at the school
• på arbejde = at work

For a room like køkkenet, i is the normal choice.

Because køkkenet is the definite form: the kitchen.

Just like:

• et køkken = a kitchen
• køkkenet = the kitchen

In this sentence, it refers to a specific kitchen, probably the one at the place where the party happened.

Samler is the present tense of samle.

Forms:

• at samle = to collect
• samler = collect / am collecting / are collecting

In Danish, the present tense is used very broadly. Depending on context, it can mean:

• a habitual action
• a present action
• a planned future action

So this sentence could mean something like:

• After the party, we collect the deposit bottles in the kitchen
• After the party, we’re collecting the deposit bottles in the kitchen
• After the party, we’ll collect the deposit bottles in the kitchen

The exact time sense depends on context.

Yes, absolutely.

That version is also correct:

• Vi samler pant i køkkenet efter festen.

The difference is mainly focus and rhythm.

• Efter festen samler vi pant i køkkenet.
  This highlights the time phrase after the party.

• Vi samler pant i køkkenet efter festen.
  This starts more neutrally with we.

Both are natural Danish.

No. Efter festen is a prepositional phrase, not a clause.

It contains:

• efter = a preposition
• festen = its object

A clause would need a verb, but Efter festen has no verb.

This matters because when a phrase like this is placed first in a main clause, Danish still applies the V2 word order:

• Efter festen samler vi pant i køkkenet.

No, not in normal Danish punctuation.

Efter festen is just an introductory prepositional phrase, and Danish does not normally require a comma after that.

So the standard form is:

• Efter festen samler vi pant i køkkenet.

A comma would usually only appear if there were a clause structure that required it, not just because a time phrase comes first.

Yes, samler is very natural here.

At samle means to gather / collect, so samler pant means gathering the bottles and cans together.

Other verbs are possible in different situations:

• rydder op = tidy up
• sorterer pant = sort the deposit bottles/cans
• afleverer pant = return the deposit bottles/cans

But if the idea is simply gathering them after the party, samler is a very good choice.