M'agrada caminar després de la feina.

Because agradar works like to be pleasing to, not like English to like.

So:

• M'agrada caminar literally means Walking is pleasing to me
• m' = to me
• agrada = is pleasing
• caminar = to walk / walking

This is why the person who experiences the liking is not the grammatical subject in the same way as in English.

A few examples:

• M'agrada el cafè. = I like coffee.
  Literally: Coffee pleases me.
• T'agrada la música? = Do you like music?
• Li agrada llegir. = He/She likes reading.

It is a shortened form of em.

• em = to me
• Before a vowel, em usually becomes m'

So:

• Em agrada → M'agrada

This contraction is very common in Catalan:

• m'agrada = I like
• t'agrada = you like
• l'he vist = I have seen him/her/it

The apostrophe helps avoid awkward vowel sequences.

Because in Catalan, as in English, an infinitive can act like a general activity.

So caminar here means:

• to walk
• or more naturally in English, walking

In M'agrada caminar, the activity itself is what is liked.

Compare:

• M'agrada caminar. = I like walking.
• M'agrada córrer. = I like running.
• M'agrada llegir. = I like reading.

Catalan often uses the infinitive where English uses the -ing form.

Because the verb agrees with the thing that is pleasing, not with the person.

In this sentence, the thing that is pleasing is caminar, which is treated as a singular idea/activity, so Catalan uses agrada.

Compare:

• M'agrada caminar. = I like walking.
  Singular activity → agrada
• M'agrada el llibre. = I like the book.
  Singular noun → agrada
• M'agraden els llibres. = I like books.
  Plural noun → agraden

So the choice between agrada and agraden depends on what comes after it.

després de means after.

In Catalan, després normally takes the preposition de before a noun or infinitive.

So:

• després de la feina = after work
• després de dinar = after eating / after lunch
• després de classe = after class

You generally should not drop de here.

Think of després de as a fixed expression.

Both relate to work, but they are not always used in exactly the same way.

• feina often means work in the sense of your job, workload, tasks, or employment situation
• treball can mean work too, but also a piece of work, labor, or academic work/project

In this sentence, la feina is very natural for work meaning my job / the workday:

• després de la feina = after work

Other examples:

• Tinc molta feina. = I have a lot of work.
• Busco feina. = I'm looking for work/a job.
• Aquest treball és difícil. = This assignment/work is difficult.

Catalan often uses the definite article where English does not.

So la feina literally means the work, but in natural English we usually just say work.

This is very common in Catalan:

• Vaig a la feina. = I’m going to work.
• Surto de la feina a les sis. = I leave work at six.
• M'agrada la música. = I like music.

So even if English omits the, Catalan may still need el/la/els/les.

Yes, but the original order is the most neutral and natural.

Standard order:

• M'agrada caminar després de la feina.

You might also hear:

• Després de la feina, m'agrada caminar.

This version puts emphasis on after work.

Both are correct, but the first one is the most straightforward sentence for a learner.

A natural way is:

• M'agrada molt caminar després de la feina.

Here:

• molt = a lot / really

So m'agrada molt means I really like or I like ... a lot.

Examples:

• M'agrada molt llegir. = I really like reading.
• M'agrada molt aquesta cançó. = I really like this song.

You add no before the verb phrase:

• No m'agrada caminar després de la feina. = I don’t like walking after work.

Structure:

• No
  • m'agrada
    • rest of sentence

Examples:

• No m'agrada el cafè. = I don’t like coffee.
• No m'agrada córrer. = I don’t like running.

A simple learner-friendly pronunciation is roughly:

• feina ≈ FAY-nuh

More precisely in Central Catalan, it is approximately /ˈfɛj.nə/.

A few pronunciation notes:

• ei here sounds like a diphthong, somewhat like ay in say, but not exactly the same as English
• the final a is often reduced to a neutral vowel sound in many accents, especially Central Catalan

You may also want to notice:

• agrada ≈ uh-GRAH-thuh in many Eastern/Central accents, or uh-GRAH-duh in accents without the th sound for d between vowels
• després has stress on the last syllable: des-PRÉS

No, not in standard Catalan.

With agradar, you normally use the infinitive directly:

• M'agrada caminar.

Not:

• M'agrada de caminar.

So in your sentence, the correct form is:

• M'agrada caminar després de la feina.

The de belongs with després de la feina, not with agrada caminar.