Learn Hardcore Dutch: De webcam staat op de tafel naast de laptop. - The webcam is on the table next to the laptop.

staan – used when something is upright / standing (on its base or edge)
liggen – used when something is lying flat or horizontally
zitten – used when something is in something, or fixed/embedded, or when a person/animal is sitting

Staan literally means “to stand”, but in sentences about location it often just means “is (standing)” and is the natural choice for many objects that rest on a surface in an upright or neutral way.

So De webcam staat op de tafel is more idiomatic than De webcam is op de tafel.
Is is not strictly wrong, but it sounds less natural in everyday Dutch here.

Could I also say De webcam ligt op de tafel instead of De webcam staat op de tafel?

Yes, that can be possible, depending on how you imagine the webcam:

If the webcam is on a little stand/base, upright, Dutch speakers will usually say:
- De webcam staat op de tafel.
If the webcam is more like a flat device lying down, then you could say:
- De webcam ligt op de tafel.

Dutch is quite picky about orientation. Using the “wrong” one is not ungrammatical, but it can sound a bit strange or give a different mental image.

Why is it de webcam and not het webcam?

In Dutch, every noun is either:

de-word (common gender)
het-word (neuter)

Webcam is a de-word, so you say:

de webcam
een webcam
de webcams

There is no logical rule you can fully rely on for all words, especially for loanwords from English. Many devices/machines are de-words:

de computer
de telefoon
de laptop
de camera
de printer
de webcam

As a learner, you simply have to memorize that webcam goes with de, not het.

Why is it de tafel and not het tafel?

Because tafel (table) is also a de-word in Dutch.

de tafel – the table
een tafel – a table
de tafels – the tables

For many basic everyday objects, you just need to learn the article together with the noun, for example:

de stoel (the chair)
de kast (the cupboard)
de deur (the door)
de tafel (the table)

There is no easy rule that would tell you “table is de, not het” – it’s a matter of vocabulary learning.

Why do we say op de tafel and not something like aan de tafel?

The prepositions have different basic meanings:

op – on (top of) a surface
aan – at / attached to / on the side of something

In your sentence, the webcam is on top of the table, so Dutch uses op:

De webcam staat op de tafel.
→ The webcam is on the table.

Aan de tafel would be used in sentences like:

We zitten aan de tafel.
→ We are at the table (sitting there).

So:

objects resting on top of the table → op de tafel
people sitting/standing around the table → often aan de tafel

What exactly does naast mean, and how is it different from bij?

Both can relate to “near”, but they are not the same:

naast = right next to, beside, usually directly adjacent
- De webcam staat naast de laptop.
  → The webcam is directly next to the laptop.
bij = near, at, with, more general closeness or association
- De webcam staat bij de laptop.
  → The webcam is (somewhere) near the laptop / together with the laptop.

So naast is more specific: it suggests the webcam and the laptop are side by side, very close. Bij is vaguer and can mean “in the same area / with / at”.

In op de tafel naast de laptop, what is next to what? Is the table next to the laptop, or the webcam next to the laptop?

Grammatically, naast de laptop can attach to either de tafel or to the whole phrase staat op de tafel. So the sentence is slightly ambiguous:

Most natural everyday reading:
The webcam and the laptop are both on the same table, and the webcam is next to the laptop on that table.
- “The webcam is on the table, next to the laptop (also on that table).”
Possible alternative reading:
The webcam is on a table, and that table is next to a laptop (e.g. the laptop is on another surface).

In real life, context usually makes it clear.
If you really want to say explicitly that the webcam is next to the laptop (on the same table), you can add a comma:

De webcam staat op de tafel, naast de laptop.

If you want to stress that the table itself is next to the laptop, you could say more clearly:

De webcam staat op de tafel die naast de laptop staat.
(more explicit but heavier style)

Could I also say De webcam staat naast de laptop op de tafel?

Yes, that sentence is also grammatically correct:

De webcam staat naast de laptop op de tafel.

Here, naast de laptop comes first, then op de tafel. It still means that the webcam is next to the laptop, and both are on the table (in most interpretations).

Both orders are possible in Dutch:

De webcam staat op de tafel naast de laptop.
De webcam staat naast de laptop op de tafel.

The first one (your original) is probably a bit more common and flows slightly more naturally.

Why don’t we start the sentence with Er, as in Er staat een webcam op de tafel?

Dutch often uses er in existential sentences (“there is / there are”), especially when introducing something new and indefinite:

Er staat een webcam op de tafel.
→ There is a webcam on the table.

In your sentence, the subject is definite: de webcam (a specific webcam already known in the situation). In that case, Dutch usually does not use er and just starts with the subject:

De webcam staat op de tafel naast de laptop.
→ The webcam is on the table next to the laptop.

So:

New, indefinite thing:
- Er staat een webcam op de tafel.
Known, definite thing:
- De webcam staat op de tafel.

When would I use een instead of de in this sentence?

Use de when you’re talking about a specific, known webcam/table/laptop.
Use een when you’re talking about any / some webcam/table/laptop (not specific).

Examples:

De webcam staat op de tafel naast de laptop.
→ The webcam is on the table next to the laptop.
(All three are specific/known.)
Een webcam staat op een tafel naast een laptop.
→ A webcam is on a table next to a laptop.
(All three are non-specific; you’re describing a situation, not particular items.)

You can also mix them, e.g.:

De webcam staat op een tafel naast de laptop.
→ The webcam is on a table next to the laptop.

How do I make this sentence plural (webcams / tables / laptops)?

Here are the common plural forms:

webcam → webcams
tafel → tafels
laptop → laptops

Some possible plural versions of the sentence:

De webcams staan op de tafel naast de laptop.
→ The webcams are on the table next to the laptop.
De webcams staan op de tafels naast de laptops.
→ The webcams are on the tables next to the laptops.
Webcams staan op tafels naast laptops.
→ Webcams are on tables next to laptops. (all indefinite, general statement)

Note that the verb also changes:

singular: De webcam staat …
plural: De webcams staan …

How do you pronounce staat, especially the aa sound?

Pronunciation tips (IPA is approximate):

staat ≈ /staːt/
- s – like English s in sit
- t – like English t
- aa – a long open “a”, somewhat like the a in British father, but held longer

For comparison:

stad (city) – /stɑt/ – short a (like u in English cup for many speakers)
staat (stands / is standing) – /staːt/ – long aa

So be sure to lengthen the vowel in staat, otherwise it may sound like a different word.