Mijn werkplek is klein, maar mijn muis en toetsenbord liggen netjes naast elkaar.

Because klein is used as a predicate adjective here, after the verb is.

• Mijn werkplek is klein = my workspace is small
• een kleine werkplek = a small workspace

In Dutch, adjectives usually get -e when they come before a noun, but not when they come after zijn, worden, blijven, etc.

Because mijn already fills that slot. In Dutch, a possessive like mijn, jouw, zijn, haar, etc. normally replaces the article.

So you say:

• mijn werkplek
• mijn muis
• mijn toetsenbord

not de mijn werkplek or het mijn toetsenbord.

For reference, the basic nouns are:

• de werkplek
• de muis
• het toetsenbord

Werkplek is a very common Dutch compound noun:

• werk = work
• plek = place, spot

So werkplek literally means work place, and in everyday use it can mean:

• workspace
• workstation
• desk area
• place where you work

Dutch often forms nouns by combining smaller words into one word, so werkplek is written as a single word.

Dutch often prefers a position verb when talking about where objects are physically located.

Here, liggen is used because a mouse and keyboard are thought of as resting flat on a surface.

So:

• liggen = to lie, to be lying
• staan = to stand
• zitten = to be situated/fixed/in
• zijn = to be

In English, you often just say are, but Dutch is more specific.

So mijn muis en toetsenbord liggen... sounds more natural than zijn... when describing their physical placement on the desk.

Because the subject is plural: mijn muis en toetsenbord.

Two things are being talked about together:

• mijn muis
• mijn toetsenbord

Together they take the plural verb liggen.

Compare:

• Mijn muis ligt naast het toetsenbord.
• Mijn muis en toetsenbord liggen naast elkaar.

So:

• singular: ligt
• plural: liggen

Here netjes means something like:

• neatly
• tidily
• in an orderly way

It describes how the mouse and keyboard are placed.

So liggen netjes naast elkaar suggests they are arranged in a tidy, organized way, not randomly or messily.

A useful point: netjes is an adverb here, even though it comes from the adjective netjes/net.

Literally:

• naast = next to, beside
• elkaar = each other / one another

Together, naast elkaar means:

• next to each other
• side by side

It is a very common expression in Dutch.

Examples:

• De stoelen staan naast elkaar. = The chairs are next to each other.
• Ze zitten naast elkaar. = They are sitting next to each other.

Yes. Mijn muis en toetsenbord is normally understood as my mouse and keyboard, meaning both are yours.

Dutch often uses one possessive before a pair of coordinated nouns like this.

If you wanted to be extra explicit, you could also say:

• mijn muis en mijn toetsenbord

But in most contexts, one mijn is enough.

Because maar is a coordinating conjunction, like but in English.

After a coordinating conjunction, the next clause keeps normal main-clause word order:

• Mijn werkplek is klein
• maar mijn muis en toetsenbord liggen netjes naast elkaar

So the verb stays in second position in the new clause: mijn ... liggen ...

This is different from subordinating conjunctions such as omdat, where the verb usually goes to the end:

• ..., omdat mijn muis en toetsenbord netjes naast elkaar liggen.

So maar does not trigger verb-final word order.

Yes. Muis is the standard Dutch word for both:

• a mouse, the animal
• a computer mouse

The context tells you which meaning is intended.

In this sentence, because it appears with toetsenbord, it clearly means the computer device.