Весной мы часто гуляем по тихой аллее в парке.

Весной is the instrumental case of весна (spring). In Russian, seasons are often used in the instrumental to mean in spring, in summer, etc.

Examples:

• весной = in spring
• летом = in summer
• осенью = in autumn
• зимой = in winter

So Весной мы часто гуляем... means In spring, we often go for walks...

Гуляем is the 1st person plural present tense of гулять. It means we walk, we go for a walk, or we stroll.

In this sentence, it usually has the sense of going for a walk / strolling, not just walking from one place to another for a practical purpose.

So:

• мы гуляем = we take walks / we go walking / we stroll

Гулять is the infinitive: to walk / to stroll / to go for a walk.

In a full sentence, you normally need a conjugated verb, so Russian uses гуляем = we walk / we are walking / we often walk.

Compare:

• гулять = to walk
• я гуляю = I walk
• мы гуляем = we walk

Часто means often, and it is an adverb. In Russian, adverbs are fairly flexible in position, but мы часто гуляем is a very natural neutral order.

You could also hear:

• Весной мы гуляем часто...

But that sounds more marked or contrastive. The version in the sentence is the most standard.

The preposition по often means along, through, or around, and with this meaning it usually takes the dative case.

Here:

• аллея = alley, path, avenue
• dative singular: аллее
• тихая becomes тихой to agree with аллее

So:

• по тихой аллее = along the quiet alley/path

Because по here requires the dative case, not the accusative.

Forms of аллея:

• nominative: аллея
• accusative: аллею
• dative: аллее

Since the phrase is по аллее, the noun must be in the dative:

• по тихой аллее

If it were a direct object, you might see аллею, but that is not what is happening here.

Adjectives in Russian must agree with the noun in gender, number, and case.

Since аллее is:

• feminine
• singular
• dative

the adjective must also be feminine singular dative:

• тихой

So:

• тихая аллея = a quiet alley/path
• по тихой аллее = along a quiet alley/path

The preposition в can mean in or into, and the case depends on the meaning.

Here it means in the park (location), so Russian uses the prepositional case:

• парк → в парке

If it meant motion into the park, Russian would normally use the accusative:

• в парк = into the park

So:

• в парке = in the park
• в парк = into the park

They describe different kinds of location.

• в парке tells you the general place: in the park
• по тихой аллее tells you the path or route of movement: along the quiet alley/path

So the full picture is:

• we often stroll
• in the park
• along a quiet path

Yes. Russian word order is more flexible than English because case endings show grammatical relationships.

The sentence:

• Весной мы часто гуляем по тихой аллее в парке.

is neutral and natural.

You could also say:

• Мы часто гуляем по тихой аллее в парке весной.
• По тихой аллее в парке мы часто гуляем весной.

These versions shift emphasis, but the core meaning stays the same.

No. Russian does not have articles like the or a/an.

So:

• в парке can mean in the park or in a park
• по тихой аллее can mean along the quiet alley/path or along a quiet alley/path

The exact meaning depends on context. In English, you have to choose an article, but Russian leaves it unstated.

Гулять is imperfective. That fits this sentence because it describes a habitual action:

• Весной мы часто гуляем... = In spring, we often go for walks...

Russian uses the imperfective for repeated, ongoing, or habitual actions.

A perfective verb would not fit as naturally here, because the sentence is not about one completed walk but about something that happens regularly.