Jeg køber ekstra toiletpapir og en blød vaskeklud, før gæsterne kommer i weekenden.

In Danish, the present tense is very often used for planned or expected future actions, especially when the time is clear from the context.

So Jeg køber ... før gæsterne kommer i weekenden means something like:

• I’m buying ... before the guests arrive this weekend
• or I’ll buy ... before the guests come this weekend

Because i weekenden gives a future time reference, Danish does not need a separate future form here.

Yes, you could say Jeg vil købe ekstra toiletpapir ..., but it changes the feel slightly.

• Jeg køber ... = a simple plan / something that is going to happen
• Jeg vil købe ... = more like I will buy ... or I intend to buy ...

In everyday Danish, the present tense is often the most natural choice for near-future plans.

Because toiletpapir here is treated as an uncountable mass noun, like water, milk, or bread in English.

So:

• ekstra toiletpapir = extra toilet paper

You would not normally use an article unless you were talking about a specific unit, for example:

• en ekstra rulle toiletpapir = an extra roll of toilet paper

Ekstra is one of those words that usually stays unchanged before a noun.

So you get:

• ekstra toiletpapir
• ekstra penge
• ekstra tid

It works a bit like extra in English: it does not need agreement endings here.

Because vaskeklud is a common-gender noun in Danish, so it takes en, not et.

That affects both the article and the adjective:

• en blød vaskeklud

Compare:

• en blød klud
• et blødt håndklæde

So:

• common gender → en blød
• neuter gender → et blødt

Because this is the form used with a singular indefinite common-gender noun:

• en blød vaskeklud

Very roughly, adjective endings work like this:

• en blød vaskeklud = singular, common gender, indefinite
• et blødt håndklæde = singular, neuter, indefinite
• den bløde vaskeklud = definite
• bløde vaskeklude = plural

So blød is exactly the form you expect after en.

Gæsterne means the guests. The speaker has specific guests in mind, not guests in general.

So:

• før gæsterne kommer = before the guests arrive

If you said før gæster kommer, it would sound more general and less tied to a specific visit.

For the same reason as køber: Danish often uses the present tense for future events when the context already shows that the action is future.

So:

• før gæsterne kommer i weekenden = before the guests come/arrive this weekend

This is very normal Danish.

Because før gæsterne kommer i weekenden is a subordinate clause, and Danish commonly places a comma before subordinate clauses.

So the sentence is divided like this:

• Jeg køber ekstra toiletpapir og en blød vaskeklud,
• før gæsterne kommer i weekenden.

This comma is much more regular in Danish than in English.

Here før means before.

It introduces the time relationship between the two actions:

• first: I buy extra toilet paper and a soft washcloth
• later: the guests arrive

So før gæsterne kommer = before the guests come/arrive

I weekenden means this weekend / at the weekend / on the weekend, depending on the English variety.

Danish commonly uses i with time expressions like this:

• i weekenden = this weekend
• i morgen = tomorrow
• i næste uge = next week in some contexts, though other patterns also exist

So even though English may use on or at, Danish uses i here.

Yes. This is standard Danish main-clause word order:

• Jeg = subject
• køber = verb
• ekstra toiletpapir og en blød vaskeklud = object
• før gæsterne kommer i weekenden = time clause

If you moved the subordinate clause to the front, the word order in the main clause would change because Danish is a V2 language:

• Før gæsterne kommer i weekenden, køber jeg ekstra toiletpapir og en blød vaskeklud.

Notice that køber comes before jeg in the main clause after the fronted phrase.

Vaskeklud means washcloth, face cloth, or sometimes flannel, depending on the variety of English.

It is made from:

• vaske = to wash
• klud = cloth

So it literally means something like washing cloth.

Yes. That is completely natural.

Here it joins:

• ekstra toiletpapir
  and
• en blød vaskeklud

English does the same:

• I’m buying extra toilet paper and a soft washcloth

There is no problem with one being uncountable and the other countable.

Grammatically yes, but kommer is much more natural in everyday Danish here.

• gæsterne kommer = the guests are coming / the guests arrive
• gæsterne ankommer = more formal, more like arrive

For ordinary visitors coming to stay or visit, kommer is the usual choice.