In die Löcher kommen zwei Dübel, damit das Regal später fest sitzt.

Because in is a two-way preposition in German: it can take either the accusative or the dative depending on the meaning.

• accusative: movement or direction into something
• dative: location in something

Here, the sentence describes the wall plugs as going into the holes, so German uses the accusative:

• in die Löcher = into the holes

If you said in den Löchern, that would mean in the holes as a location, not movement into them.

German often moves different parts of the sentence to the first position for emphasis or style. The first position does not have to be the subject.

So both of these are possible:

• In die Löcher kommen zwei Dübel.
• Zwei Dübel kommen in die Löcher.

They mean essentially the same thing, but the first version puts more focus on where the plugs go.

Because In die Löcher is in first position, the conjugated verb kommen must come next. That is why the subject zwei Dübel comes after the verb.

This is a standard verb-second pattern in main clauses.

The verb agrees with the subject, and the subject here is zwei Dübel, which is plural.

• ein Dübel kommt
• zwei Dübel kommen

Even though zwei Dübel comes after the verb, it is still the subject, so the verb must be plural.

Der Dübel is the small piece inserted into a hole in a wall so that a screw can hold securely. In British English this is often called a wall plug; in American English, something like a wall anchor is often closest, depending on the exact type.

Forms:

• singular: der Dübel
• plural: die Dübel

So zwei Dübel means two wall plugs / two anchors.

In German, when you use a number, you usually do not need an article.

So:

• zwei Dübel = two wall plugs
• drei Schrauben = three screws

You would only add an article if the context specifically calls for one, for example:

• die zwei Dübel = the two wall plugs

That would sound more specific.

Damit introduces a purpose clause. It means so that or in order that.

So:

• damit das Regal später fest sitzt = so that the shelf sits firmly later = more natural English: so that the shelf will be secure later

It explains why the two wall plugs are going into the holes.

Because damit starts a subordinate clause, and in German subordinate clauses, the conjugated verb usually goes to the end.

Main clause:

• In die Löcher kommen zwei Dübel

Subordinate clause:

• damit das Regal später fest sitzt

At the end of the subordinate clause, you get sitzt.

This is one of the most important German word-order patterns to learn.

German often uses um ... zu when the subject of both clauses is the same.

Example:

• Ich lerne viel, um die Prüfung zu bestehen. = I study a lot in order to pass the exam.

But here, the understood doer of the first clause is not the same as the subject of the second clause:

• first clause: two wall plugs go into the holes
• second clause: the shelf sits firmly

Because the subject changes, damit is the natural choice.

Fest sitzen is an idiomatic expression. Literally, sitzen means to sit, but in many contexts it means something like:

• to be positioned
• to be fitted
• to be fixed in place

So fest sitzen means:

• to sit firmly
• to be secure
• to be tightly fixed

In this sentence, it means the shelf will be firmly attached / secure, not that it is literally “sitting” like a person.

Das Regal is the subject of the subordinate clause:

• das Regal ... sitzt

The subject is in the nominative case, so it must be das Regal.

Also, Regal is a neuter noun:

• nominative singular: das Regal
• dative singular: dem Regal

So dem Regal would not work here because it is not the subject.

Später means later.

It refers to a later point in time — after the plugs and shelf have been installed.

Word order in German is flexible, especially with adverbs, but später fits naturally in the middle of the subordinate clause:

• damit das Regal später fest sitzt

You could think of it as:

• so that the shelf will later be secure

In English, we might translate it more naturally as:

• so that the shelf is secure afterwards
• so that the shelf will be firmly fixed later on

Yes. German often uses kommen in a practical, procedural way to mean that something goes or belongs somewhere.

So:

• In die Löcher kommen zwei Dübel means something like
• Two wall plugs go into the holes

This is very natural in instructions, explanations, and descriptions of how things are assembled.

English often uses go, while German may use kommen in this kind of context.

Yes, that is a very literal translation, and it reflects the German word order quite well.

But in natural English, you would usually say something more like:

• Two wall plugs go into the holes so that the shelf will be secure later.

So the literal translation is useful for understanding the structure, but it would sound unusual in everyday English.

In fest sitzt, fest behaves like an adverbial element describing how the shelf sits: firmly, securely.

But in German, words like fest are often not sharply separated into adjective versus adverb the way they are in English. The same form is commonly used in both roles.

Compare:

• ein festes Regal = a sturdy/firm shelf
• das Regal sitzt fest = the shelf is firmly fixed

So it is best to understand fest sitzen as a set expression meaning to be firmly in place.