Me gusta pasear por la playa al anochecer.

Because gustar works differently from English to like.

In Spanish, the thing that is liked is the grammatical subject, and the person who likes it is shown indirectly:

• me = to me
• gusta = is pleasing

So Me gusta pasear... literally works like Strolling... is pleasing to me.

Yo gusto usually means I am pleasing / I am liked, which is a very different idea.

Because the subject is the whole infinitive phrase:

• pasear por la playa al anochecer

An infinitive used as a subject counts as a singular idea, so Spanish uses gusta.

Compare:

• Me gusta pasear.
• Me gustan las playas.

In the second example, las playas is plural, so the verb becomes gustan.

Spanish often leaves out subject pronouns when they are not needed.

Here, me already tells you who is experiencing the liking, so yo would usually be unnecessary.

You could say A mí me gusta pasear por la playa al anochecer if you want emphasis, contrast, or clarity, but the basic sentence sounds more natural without yo.

After gustar, Spanish normally uses the infinitive to talk about liking an activity in general.

So:

• Me gusta pasear = I like strolling / I like to stroll

The form paseando is a gerund, more like strolling in the sense of while strolling or strolling around, not the normal form used after gustar for a general activity.

They are similar, but not identical.

• pasear often suggests a pleasant, leisurely walk
• caminar means to walk in a more general sense
• andar can mean to walk or to move around

So pasear por la playa gives the idea of strolling along the beach for pleasure, not just walking there as a means of getting somewhere.

Because por fits the idea of movement along, through, or around a place.

• pasear por la playa = to stroll along/around the beach
• en la playa = on the beach / at the beach
• a la playa = to the beach

So with pasear, por la playa is the most natural choice when you mean moving around that area.

Spanish uses articles more often than English does.

After a preposition like por, it is normal to say:

• por la playa
• por el parque
• por la ciudad

Leaving out the article here would sound unnatural in standard Spanish.

Al anochecer is a common expression meaning at dusk, at nightfall, or as evening turns into night.

Here, al is the contraction of a + el.

You can think of anochecer here as part of a set expression related to el anochecer, meaning dusk / nightfall.

So learners usually do best by remembering al anochecer as a chunk meaning at dusk.

Yes. Spanish word order is fairly flexible.

For example, you could also say:

• Me gusta pasear al anochecer por la playa.

That still sounds natural. The original version simply places por la playa right after pasear, which keeps the idea of strolling along the beach tightly connected.

The meaning stays basically the same; the difference is mostly one of rhythm or emphasis.

In most of Spain, the c before e is pronounced like the th in thin.

So anochecer is roughly:

• a-no-che-THER

Also:

• gusta → stress on GUS
• pasear → stress on the last syllable: pa-se-AR
• playa → usually with the y/ll sound heard in modern Spain

A rough pronunciation of the whole sentence in Peninsular Spanish would be:

• meh GUS-tah pa-se-AR por la PLA-ya al a-no-che-THER