Die Anprobe findet in der Änderungsschneiderei statt.

Anprobe is a feminine noun, so its basic article is die.

• die Anprobe = the fitting / try-on
• plural: die Anproben

This is something you mainly just have to learn with the noun. In this sentence, die Anprobe is the subject, so it stays in the nominative form.

Anprobe usually means a fitting, especially in the context of clothing being tried on, checked, or adjusted.

Typical situations:

• trying on a newly made garment
• checking whether altered clothing now fits properly
• a scheduled fitting appointment

It is related to the verb anprobieren, meaning to try on.

The expression stattfinden means to take place or to happen. It is very common for events, appointments, meetings, performances, and similar things.

So:

• Die Anprobe findet ... statt. = The fitting takes place ...
• This sounds natural for a scheduled event or appointment.

Compared with other possibilities:

• ist would just say what something is, not where it is happening.
• passiert means happens, but it is less natural here for an organized appointment.

Because stattfinden is a separable verb.

In a normal main clause in the present tense:

• the conjugated part goes to position 2: findet
• the prefix goes to the end: statt

So:

• Die Anprobe findet in der Änderungsschneiderei statt.

More examples:

• Das Konzert findet morgen statt.
• Wann findet das Treffen statt?

But when used as an infinitive or with a modal verb, it is usually written together:

• Die Anprobe wird morgen stattfinden.
• Die Anprobe kann morgen stattfinden.

Because in can take either the dative or the accusative, depending on the meaning.

Here it expresses location: the fitting takes place inside / at the alteration tailor’s shop.
For location, German uses the dative.

• in der Änderungsschneiderei = in/at the alteration tailor’s shop

If it were talking about movement into the place, you would use the accusative:

• Ich gehe in die Änderungsschneiderei. = I’m going into/to the alteration tailor’s shop.

So the contrast is:

• Where? → dative → in der
• Where to? → accusative → in die

It is feminine. The basic form is:

• die Änderungsschneiderei

But after in with a location meaning, you need the dative.
The dative form of feminine die is der.

So:

• nominative: die Änderungsschneiderei
• dative: in der Änderungsschneiderei

This is very common in German:

• in der Schule
• in der Stadt
• in der Küche

Änderungsschneiderei is a compound noun. It means an alteration tailor’s shop or place where clothes are altered.

It is built from:

• Änderung = alteration / change
• Schneiderei = tailor’s shop / tailoring business

So together it refers to a shop where clothing is adjusted, shortened, taken in, repaired, and so on.

Because German very often forms compound nouns by writing them as one word.

So instead of something like:

• alteration tailoring shop

German combines the parts:

• Änderung + Schneiderei = Änderungsschneiderei

This is completely normal in German. The last part usually tells you the basic category of the word:

• Schneiderei is the main noun
• Änderungs- describes what kind of tailoring shop it is

The basic structure is:

• Die Anprobe = subject
• findet = conjugated verb
• in der Änderungsschneiderei = place expression
• statt = separable prefix at the end

So the sentence follows the normal main-clause pattern where the conjugated verb is in second position:

Die Anprobe | findet | in der Änderungsschneiderei | statt.

This is a very common German pattern.

Grammatically, that sentence is possible, but it usually does not mean exactly the same thing.

• Die Anprobe findet in der Änderungsschneiderei statt.
  = The fitting takes place there.

• Die Anprobe ist in der Änderungsschneiderei.
  sounds less natural in most contexts and may feel incomplete or odd, because Anprobe is an event/process, not just an object sitting somewhere.

For scheduled events or appointments, stattfinden is the most natural choice.

Either may work in English, depending on style.

In German:

• in der Änderungsschneiderei

In natural English, that could be:

• in the alteration tailor’s shop
• at the alteration tailor’s shop
• sometimes simply at the tailor’s

German in often corresponds to English in or at, depending on context.

The given sentence is correct and fairly natural, but it is a bit formal or official in tone.

In everyday speech, people might also say:

• Die Anprobe ist in der Änderungsschneiderei.
• Die Anprobe ist beim Änderungsschneider.
• Die Anprobe findet beim Änderungsschneider statt.

A very natural alternative is:

• beim Änderungsschneider

That means:

• bei dem Änderungsschneider = at the alteration tailor’s / at the tailor who does alterations

A rough English-friendly guide is:

EHN-de-roongs-shny-de-rye

A few helpful points:

• Ä sounds somewhat like e in bed, though not exactly the same
• sch = sh
• ei = like English eye
• -erei is pronounced roughly -eh-RYE

If you break the word up, it becomes easier:

• Änderungs
• schneiderei

So you can practice it in parts first, then join them together.