Der er brug for hjælp i køkkenet, før gæsterne kommer.

Here der is the existential there of there is / there are. It does not mean a physical place like there over there.

So:

• Der er brug for hjælp = There is a need for help
• More natural English: Help is needed

This is a very common Danish pattern:

• Der er en bog på bordet = There is a book on the table
• Der er mange mennesker her = There are many people here

No. In this sentence, brug is a noun.

That can be confusing because Danish also has the verb at bruge, meaning to use.

Here:

• brug = need / use
• der er brug for ... = there is a need for ...

So Der er brug for hjælp literally means something like There is need for help.

A closely related expression is:

• Jeg har brug for hjælp = I need help
  Literally: I have need for help

Brug for is part of a fixed expression meaning need for.

Common patterns are:

• Der er brug for X = X is needed
• Jeg har brug for X = I need X
• Vi får brug for X = We will need X

So in your sentence:

• Der er brug for hjælp = Help is needed

It is better to learn brug for as a chunk, rather than translating word by word every time.

Because hjælp here is being used as an uncountable noun, like English help.

Compare:

• Vi har brug for hjælp = We need help
• not Vi har brug for en hjælp in this meaning

So Danish works very much like English here: you usually say help, not a help, when you mean help in general.

If you wanted to refer to a specific kind of aid or a helper, the wording would usually be different.

I means in, and it is the natural preposition for being inside a room or enclosed space.

So:

• i køkkenet = in the kitchen

This is the normal choice because a kitchen is a room you are inside.

Compare:

• i huset = in the house
• i bilen = in the car
• i køkkenet = in the kitchen

Because køkken is a neuter noun:

• et køkken = a kitchen

In Danish, the definite article is often added as an ending instead of being a separate word.

So:

• et køkken = a kitchen
• køkkenet = the kitchen

That -et ending is the normal definite singular ending for many neuter nouns.

Because gæsterne means the guests.

The noun is:

• en gæst = a guest

Its plural forms are:

• gæster = guests
• gæsterne = the guests

So -ne here marks the definite plural.

This tells you we are talking about specific guests already known from the situation: the guests who are coming.

Because Danish, like English, often uses the present tense for the future when the future meaning is clear from context.

Here the time reference is clear because of før and the situation:

• før gæsterne kommer = before the guests come / before the guests arrive

So kommer is grammatically present, but it refers to a future event.

This is very common in Danish:

• Vi ses i morgen = We’ll see each other tomorrow
• Toget kører klokken otte = The train leaves at eight

Here før is a conjunction meaning before. It introduces a subordinate clause:

• før gæsterne kommer = before the guests arrive

So the sentence is made up of:

• main clause: Der er brug for hjælp i køkkenet
• subordinate clause: før gæsterne kommer

Før can also sometimes function as a preposition in other contexts, but here it is clearly introducing a clause with a subject and verb.

Because after før, you have a subordinate clause, and subordinate clauses normally keep the order subject + verb:

• før gæsterne kommer

That is different from some main-clause patterns in Danish, where the verb can come earlier.

A useful comparison:

• Gæsterne kommer snart. = The guests are coming soon.
• Før gæsterne kommer, er der brug for hjælp. = Before the guests arrive, help is needed.

Inside the før clause, the normal order is still gæsterne kommer.

Because før gæsterne kommer is a subordinate clause.

In Danish, many writers use a comma before a subordinate clause like this. So:

• Der er brug for hjælp i køkkenet, før gæsterne kommer.

You may also see Danish written without that comma, depending on which official comma system the writer follows:

• Der er brug for hjælp i køkkenet før gæsterne kommer.

So if you see both, that is normal.

Yes:

• Før gæsterne kommer, er der brug for hjælp i køkkenet.

That is completely natural.

But notice what happens in the main clause after the fronted phrase: Danish uses verb-second word order, so you get:

• er der
• not der er

So:

• Der er brug for hjælp i køkkenet, før gæsterne kommer.
• Før gæsterne kommer, er der brug for hjælp i køkkenet.

Both are correct, but the second one puts more focus on the time element.

A rough pronunciation guide for an English speaker could be:

• Der er brug for hjælp i køkkenet, før gæsterne kommer
• roughly: dair air broo' for hyelp ee KERK-uh-ned, fur GES-tur-nuh KOM-mer

A few tricky parts:

• hjælp begins with hj-, which sounds a bit like a softened y sound to English ears
• ø in køkkenet is a front rounded vowel that English does not really have
• æ in gæsterne sounds somewhat like the vowel in cat, but not exactly
• Danish pronunciation is often less fully pronounced than the spelling suggests

If you are learning the sentence actively, it is best to listen to native audio and shadow it rather than relying only on spelling.