Hvis der er kiks tilbage i skabet, tager min datter dem med ud på terrassen.

Hvis means if and introduces a condition.

In this sentence, Hvis der er kiks tilbage i skabet sets up the condition under which the main action happens. Danish uses hvis much like English if in ordinary conditional sentences.

For example:

• Hvis det regner, bliver vi hjemme. = If it rains, we stay home.
• Hvis hun kommer, bliver jeg glad. = If she comes, I’ll be happy.

So here, the idea is: under the condition that there are biscuits/crackers left in the cupboard, the daughter takes them outside.

Der er is the Danish equivalent of there is / there are in existential sentences.

So:

• Der er en bog på bordet. = There is a book on the table.
• Der er kiks i skabet. = There are biscuits in the cupboard.

In your sentence:

• Hvis der er kiks tilbage i skabet... literally means If there are biscuits left in the cupboard...

The word der here does not mean there in a location sense. It is just part of the structure used to say that something exists or is present.

Kiks here is an indefinite plural noun: biscuits/crackers in a general sense.

Danish often uses a bare plural noun where English might also just say biscuits:

• der er kiks tilbage = there are biscuits left

You do not need an article here because the sentence is not talking about the biscuits as a specifically identified set at that point; it is simply saying that some biscuits remain.

A few useful comparisons:

• kiks = biscuits/crackers
• nogle kiks = some biscuits
• kiksene = the biscuits

You could say Hvis der er nogle kiks tilbage i skabet..., but it is not necessary.

Tilbage means left, remaining, or left over in this context.

So:

• kiks tilbage = biscuits left / remaining biscuits

Examples:

• Er der kaffe tilbage? = Is there any coffee left?
• Der er kun to billetter tilbage. = There are only two tickets left.

It often appears after the noun or quantity it refers to:

• penge tilbage = money left
• mad tilbage = food left

Because skabet means the cupboard / the cabinet.

Danish usually puts the definite article at the end of the noun:

• et skab = a cupboard
• skabet = the cupboard

So:

• i skabet = in the cupboard

This is a very important Danish pattern:

• en stol → stolen
• et hus → huset
• en terrasse → terrassen

This is because Danish is a V2 language in main clauses. That means the finite verb usually comes in the second position.

The sentence starts with a subordinate clause:

• Hvis der er kiks tilbage i skabet

After that whole clause, the main clause begins, and the finite verb comes first:

• tager min datter dem med ud på terrassen

So the order is:

1. fronted element: Hvis der er kiks tilbage i skabet
2. finite verb: tager
3. subject: min datter

This is very common in Danish:

• I dag kommer han. = Today he is coming.
• Når jeg har tid, læser jeg. = When I have time, I read.

If the main clause stood alone, it would be:

• Min datter tager dem med ud på terrassen.

Because dem is the object form, while de is the subject form.

Here, the biscuits are receiving the action:

• the daughter takes them

So Danish uses dem:

• de = they
• dem = them

Examples:

• De ligger i skabet. = They are lying in the cupboard.
• Hun tager dem. = She takes them.

So in your sentence, dem correctly refers back to kiks.

Tage med means take along, bring along, or take with one.

It is a very common verb + particle combination in Danish:

• Jeg tager min bog med. = I’m taking my book with me.
• Kan jeg tage en ven med? = Can I bring a friend?

In your sentence:

• tager min datter dem med = my daughter takes them along / takes them with her

Notice that med can be separated from tager, especially when an object comes in between:

• Hun tager dem med.
• Jeg tager kaffen med.

Because Danish often uses the present tense for general truths, habits, and even future meaning when the context is clear.

Here the sentence describes a regular or likely action:

• Hvis der er ... tager ...

English can also do this:

• If there are any biscuits left, my daughter takes them outside. or more naturally,
• If there are any biscuits left, my daughter will take them outside.

Danish does not need a special future form here. The present tense works perfectly well.

This is an important distinction.

• ud på terrassen describes movement out onto the terrace
• ude på terrassen describes location out on the terrace

So:

• Hun går ud på terrassen. = She goes out onto the terrace.
• Hun sidder ude på terrassen. = She is sitting out on the terrace.

In your sentence, the daughter is moving the biscuits from inside to outside, so ud på terrassen is the natural choice.

Because a terrace is thought of as a surface or open area, so Danish uses på = on.

• på terrassen = on the terrace
• på altanen = on the balcony

By contrast, i is used for being inside an enclosed space:

• i huset = in the house
• i skabet = in the cupboard

So the contrast in your sentence is very natural:

• i skabet = in the cupboard
• på terrassen = on the terrace

Because when Danish uses a possessive like min, the noun normally stays in the indefinite form.

So:

• min datter = my daughter not
• min datteren

Compare:

• min bil = my car
• mit hus = my house
• mine bøger = my books

This is different from English only in form, not meaning. The possessive already makes the noun definite enough, so Danish does not usually add the definite ending as well.

Yes, in normal written Danish, a subordinate clause is separated from the main clause with a comma here:

• Hvis der er kiks tilbage i skabet, tager min datter dem med ud på terrassen.

The comma marks the end of the if-clause and the start of the main clause.

This is very standard in Danish writing, especially when a subordinate clause comes first.