Lägg servetterna på köksbordet innan gästerna kommer.

Lägg is the imperative form of the verb lägga (to put / to lay).

In Swedish, the imperative is used for commands and instructions:

• Lägg servetterna ... = Put the napkins ...
• Stäng dörren. = Close the door.
• Kom hit. = Come here.

So:

• lägga = infinitive, to put
• lägger = present tense, puts / is putting
• lägg = command form, put!

English often uses the bare verb for commands, and Swedish does something similar.

Servetterna means the napkins, while servetter means just napkins.

Swedish usually adds the definite article to the end of the noun instead of using a separate word like the.

Here is the pattern:

• en servett = a napkin
• servetten = the napkin
• servetter = napkins
• servetterna = the napkins

So Lägg servetterna ... specifically means Put the napkins ..., not just Put napkins ...

Swedish very often forms compound nouns by joining words together.

So:

• kök = kitchen
• bord = table
• köksbord = kitchen table

Then the definite ending is added:

• köksbordet = the kitchen table

This is very normal in Swedish. English often writes similar ideas as separate words, but Swedish commonly combines them into one:

• sjukhus = hospital
• sommarjobb = summer job
• köksbord = kitchen table

So på köksbordet literally breaks down as on kitchen-table-the, but in natural English it means on the kitchen table.

Because på means on, and a table is treated as a surface.

So:

• på bordet = on the table
• på golvet = on the floor
• på hyllan = on the shelf

By contrast, i means in and is used for something inside something:

• i lådan = in the drawer
• i köket = in the kitchen
• i väskan = in the bag

Since napkins are being placed on top of the table, på is the correct preposition.

Innan means before.

It introduces a time clause:

• innan gästerna kommer = before the guests come / before the guests arrive

So the structure is:

• Lägg servetterna på köksbordet = main command
• innan gästerna kommer = time clause telling you before when

You can use innan in many similar sentences:

• Ät innan du går. = Eat before you go.
• Ring mig innan du åker. = Call me before you leave.

Because after innan, Swedish uses subordinate clause word order.

In a normal main clause, Swedish often has the verb in second position:

• Gästerna kommer snart. = The guests are coming soon.
• Snart kommer gästerna. = Soon the guests are coming.

But after a subordinating word like innan, the clause keeps the subject before the verb:

• innan gästerna kommer

This is the normal pattern in subordinate clauses.

So:

• innan gästerna kommer = correct
• innan kommer gästerna = not correct here

It can be understood as either come or arrive, depending on context.

In this sentence, natural English is often:

• before the guests arrive

Even though the Swedish verb is literally come, that is often how Swedish expresses arrival in everyday language.

So:

• gästerna kommer = the guests are coming
• in this context: before the guests arrive

Both ideas are closely connected, and the intended meaning is clear from the situation.

Gästerna means the guests, while gäster means guests in a more general or indefinite sense.

Compare:

• gäster = guests
• gästerna = the guests

In this sentence, it refers to specific guests that both speaker and listener know about, so the definite form is natural:

• innan gästerna kommer = before the guests arrive

If you said innan gäster kommer, it would sound more general, like before guests come or before any guests arrive.

The base singular form is en gäst = a guest.

Its forms are:

• en gäst = a guest
• gästen = the guest
• gäster = guests
• gästerna = the guests

The plural changes the vowel slightly:

• gäst → gäster

This kind of plural pattern is common in Swedish nouns.

Yes, it is a completely natural and correct sentence.

It sounds like a normal instruction someone might give at home before visitors arrive.

The structure is straightforward:

• Lägg = command
• servetterna = the napkins
• på köksbordet = on the kitchen table
• innan gästerna kommer = before the guests arrive

A native speaker would understand it immediately, and it sounds idiomatic.

Yes. If it is already clear which napkins you mean, Swedish could use a pronoun:

• Lägg dem på köksbordet innan gästerna kommer. = Put them on the kitchen table before the guests arrive.

But in your sentence, servetterna is used to name the object clearly. That is often helpful when giving instructions, especially if several things are being discussed.

So both are possible, but they are used in slightly different contexts:

• lägg servetterna = say exactly what to put
• lägg dem = use them when the object is already known