Am Morgen miaut die Katze leise vor dem Schlafzimmer.

Am is the contraction of an dem.

In time expressions, German often uses am with parts of the day:

• am Morgen
• am Abend
• am Nachmittag

So Am Morgen is a very normal way to say in the morning.

English speakers sometimes expect im Morgen, but that is not the usual expression here. Im is used with some other time expressions, such as im Sommer or im Januar.

German main clauses follow the verb-second rule. That means the conjugated verb must be in the second position.

Here, Am Morgen is placed first:

• Am Morgen = position 1
• miaut = position 2

So the subject die Katze comes after the verb:

• Am Morgen miaut die Katze ...

This is completely normal in German. If the subject came first, you could also say:

• Die Katze miaut am Morgen leise vor dem Schlafzimmer.

Yes. In German, the subject does not have to come before the verb.

Die Katze is still the subject because it is in the nominative case. In this sentence, die Katze is the thing doing the action of miauen.

So word order does not change its role here:

• Die Katze miaut ...
• Am Morgen miaut die Katze ...

In both cases, die Katze is the subject.

The infinitive is miauen, meaning to meow.

Miaut is the third-person singular present form, used with die Katze:

• ich miaue
• du miaust
• er/sie/es miaut

So die Katze miaut means the cat meows / is meowing depending on context.

Here leise is being used as an adverb, not as an adjective directly describing a noun.

In German, adjectives used as adverbs usually do not change their form:

• Die Katze miaut leise.
• Er spricht leise.
• Sie singt schön.

But when an adjective stands before a noun, it gets an ending:

• die leise Katze

So in your sentence, leise stays unchanged because it describes how the cat meows.

The preposition vor is a two-way preposition. That means it can take either:

• dative for a location
• accusative for a direction/movement toward somewhere

Here the cat is meowing in front of the bedroom, so this is a location. That is why German uses the dative:

• vor dem Schlafzimmer

If there were movement toward that place, you might use the accusative:

• Die Katze läuft vor das Schlafzimmer.

So:

• where? → dative
• to where? → accusative

Schlafzimmer is a neuter noun: das Schlafzimmer.

After vor in a location meaning, you need the dative case. The dative singular article for a neuter noun is dem:

• nominative: das Schlafzimmer
• dative: dem Schlafzimmer

So:

• vor dem Schlafzimmer

That is why the article changes from das to dem.

Yes. Vor can have different meanings depending on context.

Very common meanings are:

• in front of a place or object
• before in time

Examples:

• vor dem Haus = in front of the house
• vor dem Essen = before the meal

In your sentence, vor dem Schlafzimmer is clearly the spatial meaning.

Yes, absolutely.

That version is also correct:

• Die Katze miaut am Morgen leise vor dem Schlafzimmer.

The difference is mainly emphasis or focus.

• Am Morgen miaut die Katze ... puts more attention on when
• Die Katze miaut am Morgen ... starts more neutrally with the subject

German allows quite a lot of movement in word order, as long as the verb-second rule is respected in a main clause.

Because all nouns are capitalized in German.

So you write:

• die Katze
• der Morgen
• das Schlafzimmer

This is one of the most noticeable spelling rules in German.

They are similar, but not always exactly identical.

• am Morgen often refers to in the morning in a specific situation or time frame
• morgens often means in the mornings or every morning / generally in the morning

Examples:

• Am Morgen miaut die Katze ... = in the morning
• Morgens miaut die Katze ... = in the mornings / every morning

In real usage, though, there can be overlap, and context helps decide the meaning.

Words like leise often come in the middle part of the sentence, after the verb and usually after the subject, though exact placement can vary.

In your sentence:

• Am Morgen miaut die Katze leise vor dem Schlafzimmer.

This sounds natural because:

• time phrase first
• verb second
• subject next
• manner adverb leise
• place phrase vor dem Schlafzimmer

A useful general pattern is:

• time – verb – subject – manner – place

But this is only a tendency, not a rigid rule for every sentence.