Hun står på en stige, mens jeg holder den.

Because Danish often prefers a position verb where English would simply use be.

• stå = stand
• sidde = sit
• ligge = lie

So Hun står på en stige is more natural than Hun er på en stige if you want to describe her physical position. Since she is upright on the ladder, står fits well.

Hun er på en stige is not impossible, but it is less specific and less natural in this context.

Står is the present tense of stå (to stand).

A useful thing for English speakers: Danish verbs do not change for person.

• jeg står = I stand / I am standing
• hun står = she stands / she is standing
• vi står = we stand / we are standing

So the same present-tense form is used with all subjects.

Because stige is a common-gender noun in Danish.

That means:

• indefinite singular: en stige = a ladder
• pronoun referring back to it: den = it

In Danish, singular nouns are either:

• common gender → en, later den
• neuter gender → et, later det

So because stige is an en-word, you get en stige and den.

If you were using the definite noun instead of a pronoun, it would be stigen = the ladder.

Because Danish, like English, normally uses på for being on a ladder.

So:

• på en stige = on a ladder

This is one of those cases where Danish and English match nicely. You do not need a different preposition here.

Mens means while.

It connects two actions that happen at the same time:

• Hun står på en stige
• mens jeg holder den

So the full sentence means that the two actions are simultaneous.

Grammatically, mens introduces a subordinate clause. After mens, Danish normally keeps the subject before the verb:

• mens jeg holder den

Not:

• mens holder jeg den

If you put the mens-clause first, you get:

• Mens jeg holder den, står hun på en stige.

Because the normal order here is:

• subject + verb + object

So:

• jeg = subject
• holder = verb
• den = object

That gives jeg holder den = I’m holding it.

For an English speaker, this is fairly familiar. The important thing is that after mens, Danish does not invert the subject and verb here.

Here holder means hold in the physical sense: to hold / support / steady the ladder.

The verb holde can mean several things in Danish, depending on context, for example:

• hold something in your hand
• keep
• stop
• last

But in this sentence, the meaning is clearly physical: I am holding the ladder steady.

In this sentence, den means it, because it refers back to en stige.

Danish den can sometimes also be part of expressions that correspond to that or the one, but here it is simply the pronoun referring to the ladder.

So:

• en stige → den

A good way to think of it is: once the ladder has been mentioned, Danish can refer back to it with den.

Yes, often you can.

Both mens and imens can mean while. In many everyday sentences, mens is the simplest and most common choice, so it is a very good default word for learners.

So this would also be understandable:

• Hun står på en stige, imens jeg holder den.

But mens is usually the safest word to learn first.

Because Danish punctuation often puts a comma before a subordinate clause, and mens jeg holder den is a subordinate clause.

However, Danish comma usage can vary depending on the comma system being followed, so learners may see both:

• Hun står på en stige, mens jeg holder den.
• Hun står på en stige mens jeg holder den.

So the comma here is normal, but you may also encounter sentences without it.