Ich finde es entspannend, am Abend auf dem Balkon zu sitzen und den Duft der Rosen zu genießen.

Here es is a placeholder object. German often uses es when the real content of the sentence comes later as an infinitive clause.

So:

• Ich finde es entspannend, ... = I find it relaxing to ...

The real thing being described as relaxing is the activity:

• am Abend auf dem Balkon zu sitzen und den Duft der Rosen zu genießen

Without es, the sentence would sound incomplete or unnatural in standard German.

Entspannend means relaxing — something causes relaxation.

• Das ist entspannend. = That is relaxing.

Entspannt usually means relaxed — describing a person or mood/state.

• Ich bin entspannt. = I am relaxed.

So in this sentence, the activity is relaxing, not relaxed, which is why entspannend is the right word.

Because they belong to an infinitive clause with zu.

After expressions like:

• Ich finde es schön, ...
• Ich finde es schwer, ...
• Ich finde es entspannend, ...

German often uses zu + infinitive to say to do something.

So:

• zu sitzen = to sit
• zu genießen = to enjoy

This is very similar to English to sit and to enjoy.

The comma separates the main clause from the infinitive clause.

Main clause:

• Ich finde es entspannend

Infinitive clause:

• am Abend auf dem Balkon zu sitzen und den Duft der Rosen zu genießen

In German, infinitive clauses with zu are usually set off with a comma, especially when they depend on a phrase like ich finde es entspannend.

Am Abend means in the evening or in the evenings, depending on context.

Am is just the contraction of:

• an dem → am

So:

• an dem Abend = on that evening
• am Abend = in the evening / in the evening time

This is very common in German:

• am Morgen = in the morning
• am Nachmittag = in the afternoon
• am Abend = in the evening

Because this sentence describes a location, not movement toward a destination.

German uses different cases after two-way prepositions like auf:

• Dative for location: where?
• Accusative for direction/movement: where to?

Here the meaning is to sit on the balcony, so it is a location:

• auf dem Balkon = on the balcony

Compare:

• Ich sitze auf dem Balkon. = I am sitting on the balcony.
• Ich gehe auf den Balkon. = I go onto the balcony.

Because Duft is a masculine noun: der Duft.

Here it is the direct object of genießen:

• den Duft genießen = to enjoy the scent

Masculine nouns change in the accusative:

• nominative: der Duft
• accusative: den Duft

So den is used because Duft is masculine and is the thing being enjoyed.

Der Rosen is the genitive plural, showing possession or association.

• der Duft der Rosen = the scent of the roses

Breakdown:

• die Rosen = the roses
• der Rosen = of the roses

So this is a very typical German pattern:

• die Farbe des Himmels = the color of the sky
• der Geschmack des Weins = the taste of the wine
• der Duft der Rosen = the scent of the roses

Because both infinitives belong to the same subject and are joined by und.

The whole activity is:

• am Abend auf dem Balkon zu sitzen
• und den Duft der Rosen zu genießen

Both actions are things I find relaxing. German does not need to repeat the subject here, just like English usually would not:

• to sit on the balcony and enjoy the scent of the roses

Not:

• to sit on the balcony and to enjoy...
• to sit on the balcony and I enjoy...

That is normal in a German infinitive clause with zu.

In this kind of clause, the infinitive usually comes at the end:

• ... auf dem Balkon zu sitzen
• ... den Duft der Rosen zu genießen

This is one of the major word-order differences from English. German often pushes the verb toward the end in subordinate structures.

Yes. German word order is flexible, especially with time, place, and manner phrases.

For example, you could also say:

• Ich finde es entspannend, auf dem Balkon am Abend zu sitzen und den Duft der Rosen zu genießen.

This still sounds natural, though am Abend auf dem Balkon is a very smooth and idiomatic order.

A common tendency in German is:

• time before place

So:

• am Abend auf dem Balkon

fits that pattern well.

Yes. Both can mean smell, but they are not exactly the same.

• Duft usually suggests a pleasant fragrance
• Geruch is more neutral and can even sound unpleasant depending on context

So with roses, Duft is the natural choice because roses are associated with a pleasant scent.

• der Duft der Rosen = the fragrance/scent of the roses

Yes, often you can.

• am Abend = in the evening
• abends = in the evenings / evenings

The difference is slight and depends on context.

In this sentence:

• Ich finde es entspannend, am Abend ... sounds like in the evening
• Ich finde es entspannend, abends ... can sound more like a general habit: in the evenings

Both are possible, but am Abend is a very natural choice here.