Anstatt sofort einen Vertrag zu unterschreiben, möchte meine Schwester die Wohnung zuerst noch einmal besichtigen.

Anstatt means instead of. Here it introduces an infinitive construction: anstatt ... zu + infinitive, which is a very common way to say instead of doing something.

So:

• Anstatt sofort einen Vertrag zu unterschreiben = Instead of signing a contract immediately

The whole opening part functions like an adverbial phrase explaining the alternative action.

You may also see statt used similarly:

• Statt sofort einen Vertrag zu unterschreiben, ...

That is slightly more common in everyday German, but anstatt is perfectly correct.

In German, after expressions like anstatt, ohne, and um, you usually use an infinitive with zu.

So:

• anstatt ... zu unterschreiben = instead of signing

This is similar to how English often uses the -ing form after instead of.

More examples:

• Ohne etwas zu sagen, ging er weg.
  = Without saying anything, he left.

• Um pünktlich zu sein, müssen wir jetzt gehen.
  = In order to be on time, we have to go now.

Because unterschreiben is a transitive verb and takes a direct object.

• einen Vertrag unterschreiben = to sign a contract

The thing being signed is the direct object, so it is in the accusative.

That is why you get:

• ein Vertrag → nominative
• einen Vertrag → accusative

Since Vertrag is masculine, the article changes from ein to einen in the accusative singular.

For the same reason: besichtigen also takes a direct object.

• die Wohnung besichtigen = to inspect/view the apartment

Here, die Wohnung is the thing being viewed, so it is the direct object.

Because Wohnung is feminine, the article is:

• nominative: die
• accusative: die

So the article does not change visibly, even though the noun is accusative.

German main clauses follow the V2 rule: the conjugated verb must be in the second position.

The first position can be taken by many things, not just the subject. In this sentence, the whole phrase

• Anstatt sofort einen Vertrag zu unterschreiben

occupies position 1.

So the conjugated verb must come next:

• ... möchte ...

Then the subject comes after it:

• ... möchte meine Schwester ...

This is completely normal German word order.

Basic structure:

• [Position 1] [conjugated verb] [subject] ...

So here:

• Anstatt sofort einen Vertrag zu unterschreiben = position 1
• möchte = position 2
• meine Schwester = subject

Because the sentence does not begin with the subject. It begins with the Anstatt phrase.

In German main clauses, when something other than the subject takes first position, the conjugated verb still stays in second position, and the subject usually comes right after the verb.

Compare:

• Meine Schwester möchte die Wohnung noch einmal besichtigen.
• Anstatt sofort einen Vertrag zu unterschreiben, möchte meine Schwester die Wohnung noch einmal besichtigen.

Both are correct. The second version puts emphasis on the instead of... idea.

Möchte is the polite/subtle form often used to express a wish, intention, or preference:

• ich möchte = I would like
• sie möchte = she would like

So:

• meine Schwester möchte die Wohnung ... besichtigen = my sister would like to inspect the apartment ...

German will usually means wants to in a stronger, more direct sense:

• Meine Schwester will die Wohnung noch einmal besichtigen. = My sister wants to inspect the apartment again.

So möchte sounds softer and often more natural in many contexts.

Because this is a clause with the modal verb möchte. With modal verbs in German:

• the conjugated modal verb goes in the usual verb position
• the main infinitive goes to the end

So:

• möchte = conjugated modal verb
• besichtigen = main verb in the infinitive at the end

Pattern:

• Sie möchte die Wohnung besichtigen.

This is one of the most important German sentence patterns.

Together they mean something like:

• first, one more time
• or more naturally in English here: to view the apartment again first

The two words add different ideas:

• zuerst = first / first of all
• noch einmal = again / one more time

So the sentence means that before signing a contract, her preferred next step is to inspect the apartment again first.

You could think of the logic as:

1. inspect the apartment again
2. only after that, maybe sign the contract

They are often similar, but not always identical.

• noch einmal literally means once more / one more time
• wieder usually means again

In many contexts, either can work:

• die Wohnung noch einmal besichtigen
• die Wohnung wieder besichtigen

But noch einmal often emphasizes one additional time, which fits this sentence very well.

So here noch einmal sounds especially natural because the idea is that she wants to inspect it one more time before deciding.

Besichtigen is a very common verb for officially or deliberately viewing something such as:

• an apartment
• a house
• a building
• a museum
• a tourist site

It suggests a more purposeful inspection or viewing.

So:

• eine Wohnung besichtigen = to view/inspect an apartment

By contrast:

• sehen = to see
• ansehen = to look at / watch / take a look at

For apartment-hunting, besichtigen is the standard choice.

Yes.

You can say:

• Statt sofort einen Vertrag zu unterschreiben, möchte meine Schwester die Wohnung zuerst noch einmal besichtigen.

This means the same thing.

In modern everyday German, statt is often more common, while anstatt can sound a little more formal or literary depending on context. Both are correct.

Because the sentence begins with an infinitive construction that is separated from the main clause.

The first part:

• Anstatt sofort einen Vertrag zu unterschreiben

is an extended infinitive phrase with zu. In German, such constructions are normally set off with a comma, especially when introduced by words like:

• anstatt
• ohne
• um

So the comma helps mark the boundary before the main clause:

• ..., möchte meine Schwester ...

Yes, in principle German allows that kind of flexibility, though the original order is very natural.

For example:

• Meine Schwester möchte die Wohnung zuerst noch einmal besichtigen, anstatt sofort einen Vertrag zu unterschreiben.

This is also correct and means the same thing.

The difference is mainly one of emphasis:

• putting the Anstatt phrase first highlights the contrast immediately
• putting it later makes the sentence start more neutrally with the subject

The core sentence is:

• Meine Schwester möchte die Wohnung besichtigen. = My sister would like to inspect the apartment.

Then extra information is added:

• Anstatt sofort einen Vertrag zu unterschreiben = instead of signing a contract immediately
• zuerst = first
• noch einmal = again / one more time

So the full sentence is built from a simple main clause plus additional modifiers. This is a useful way to understand long German sentences: find the core first, then add the surrounding pieces.