Jeg går ned med skraldeposen, før gæsterne kommer.

Because Danish very often uses the present tense for planned or expected future events.

So:

• Jeg går ned med skraldeposen can mean I’m taking the trash bag down / I’ll take the trash bag down
• før gæsterne kommer means before the guests arrive

This is completely normal Danish. English does something similar in sentences like I’m leaving tomorrow or The guests arrive at six.

Literally, it means I go down with the trash bag.

In natural English, though, you would usually translate it more idiomatically as:

• I’ll take the trash bag down
• I’m taking the trash bag down
• possibly I’ll take out the trash depending on context

So the Danish focuses on the speaker’s movement: going down, while English often prefers take.

With gå, Danish normally uses med to show that you are bringing or carrying something with you.

So:

• gå med noget = go with something / bring something along
• Jeg går ned med skraldeposen = I’m going down, taking the trash bag with me

Without med, the sentence would not work naturally.

Compare:

• Jeg går ned med skraldeposen = I go down with the trash bag
• Jeg tager skraldeposen ned = I take the trash bag down

Both are possible, but they are built differently.

Ned means down and gives a sense of direction.

It often suggests that the speaker is going:

• downstairs
• down to the courtyard
• down to the trash room or bins

So the sentence may sound especially natural if the speaker lives in an apartment building and needs to go downstairs with the bag.

If the idea were more about going out with the trash, Danish might also use:

• gå ud med skraldet = take out the trash

Because Danish usually puts the definite article at the end of the noun.

So:

• en skraldepose = a trash bag
• skraldeposen = the trash bag

This is one of the big differences from English. Instead of a separate word like the, Danish often adds a suffix:

• en pose → posen
• en gæst → gæsten
• et hus → huset

Here, skraldeposen means a specific trash bag, presumably the one the speaker is about to take down.

Gæsterne means the guests, not just guests in general.

That definite form is used because these are specific, known guests—the people expected to arrive.

Compare:

• før gæsterne kommer = before the guests arrive
• når gæster kommer = when guests come / when guests arrive in general

In this sentence, the speaker clearly has particular guests in mind, so gæsterne is the natural choice.

Because Danish normally writes compound nouns as one word.

So:

• skrald = trash
• pose = bag
• skraldepose = trash bag

Then the definite ending is added:

• skraldepose → skraldeposen

This is very common in Danish. English often writes these as two words, but Danish usually combines them into one.

Because før introduces a subordinate clause: før gæsterne kommer.

In Danish, commas around subordinate clauses depend on the comma system being used:

• with traditional/grammatical comma, you write a comma before the subordinate clause
• with the newer system without start comma, you can leave it out

So both of these can be acceptable, depending on style:

• Jeg går ned med skraldeposen, før gæsterne kommer.
• Jeg går ned med skraldeposen før gæsterne kommer.

The version with the comma is very common and perfectly correct.

Yes. Før introduces a subordinate clause, and subordinate clauses in Danish do not use the normal main-clause verb-second pattern.

Here you get:

• før gæsterne kommer
• subject: gæsterne
• verb: kommer

That is the normal subordinate-clause order.

A learner often notices that Danish main clauses can move elements around more freely, but after words like før, at, fordi, når, and hvis, the structure becomes more straightforward.

Yes, in this sentence inden would work very well.

Both can mean before:

• før gæsterne kommer
• inden gæsterne kommer

In many everyday contexts, they are very close in meaning. Inden can sometimes feel a little more like before/by the time, but here the difference is small.

So this would also sound natural:

• Jeg går ned med skraldeposen, inden gæsterne kommer.

Yes, it is natural, especially if the speaker is emphasizing going down with the trash bag.

But Danish also very commonly says:

• Jeg går ud med skraldet = I’m taking out the trash

The difference is mainly in focus:

• skraldeposen = the trash bag specifically
• skraldet = the trash in general
• ned = down
• ud = out

So the original sentence sounds natural, but it is one of several possible everyday ways to express the idea.