Jeg skal ordne nogle små ting derhjemme, før gæsterne kommer.

Here, skal is a modal verb and means something like have to, need to, or am supposed to.

So Jeg skal ordne... is not the formal English I shall.... It is much closer to:

• I need to take care of...
• I have to sort out...
• I’m going to deal with...

In this sentence, it suggests a planned or necessary action before the guests arrive.

Because skal is a modal verb, and modal verbs in Danish are followed by the bare infinitive.

So you say:

• Jeg skal ordne
• Jeg kan komme
• Jeg vil spise

not:

• Jeg skal at ordne

This works a lot like English:

• I must go
• I can swim

not I must to go.

Ordne is a very common verb with a broad meaning. It can mean:

• arrange
• sort out
• take care of
• fix
• put in order

In Jeg skal ordne nogle små ting derhjemme, it most naturally means something like take care of or sort out a few small tasks at home.

It does not necessarily mean repairing something physical. It can just mean dealing with practical things.

Because ting is being used as a plural count noun here.

• nogle = some with plural countable nouns
• noget = some with uncountable nouns or neuter singular
• nogen is used in other contexts, often in negatives, questions, or with singular/common-gender meanings depending on usage

So:

• nogle ting = some things
• noget vand = some water

Since the sentence is talking about some small things/tasks, nogle is the correct choice.

Because små is the plural form of lille.

This adjective is a bit irregular:

• singular: lille
• plural: små

So:

• en lille ting = a small thing
• nogle små ting = some small things

That is why you get små here.

In this sentence, ting is plural.

The noun ting has the same form in singular and plural in many contexts, so you often have to look at the surrounding words:

• en ting = a thing
• nogle ting = some things

Here, nogle and små clearly show that it is plural.

derhjemme means at home.

In many situations, derhjemme and hjemme are very close in meaning. Derhjemme can feel a little more specific or a little more like back at home / at home there, but in everyday speech the difference is often small.

So:

• Jeg er hjemme = I’m at home
• Jeg er derhjemme = I’m at home

In your sentence, derhjemme sounds very natural and emphasizes that these are things to do at home.

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

So:

• en gæst = a guest
• gæsten = the guest
• gæster = guests
• gæsterne = the guests

That -ne ending is the plural definite article.

English uses a separate word (the guests), but Danish often attaches the definiteness directly to the noun.

Because Danish very often uses the present tense for future meaning when the future event is understood from context.

So før gæsterne kommer literally uses present tense, but it means before the guests come/arrive.

This is actually similar to English. We usually say:

• before the guests come

not:

• before the guests will come

So Danish and English work similarly here.

Because før introduces a subordinate clause, and in a normal subordinate clause the subject usually comes before the verb:

• gæsterne kommer

Danish inversion such as kommer gæsterne... is mainly something you see in main clauses after another element has been placed first.

So:

• main clause: Nu kommer gæsterne
• subordinate clause: før gæsterne kommer

That is why gæsterne comes before kommer here.

Not always.

In Danish, you may see two accepted comma styles:

• with start comma: Jeg skal ordne nogle små ting derhjemme, før gæsterne kommer.
• without start comma: Jeg skal ordne nogle små ting derhjemme før gæsterne kommer.

Both are possible, depending on the comma system being used.

So if you see the sentence with or without that comma, it does not change the meaning.