Después de comer, me gusta hacer la siesta en el sofá.

Because después normally needs de before a noun or an infinitive.

So in Spanish you say:

• después de comer = after eating / after lunch
• después de clase = after class
• después de trabajar = after working

Without de, it sounds incorrect here.

After después de, Spanish often uses an infinitive when the action is meant in a general sense.

So después de comer literally works like after eating.

This is very common in Spanish:

• antes de salir = before leaving
• después de cenar = after having dinner
• antes de estudiar = before studying

In this sentence, comer does not mean to eat in a dictionary-style way; it means the activity of eating.

It can often be understood as either, depending on context.

In everyday Spanish, especially in Spain, comer can refer to the main meal of the day, which is often lunch. So:

• después de comer often means after lunch
• but literally it is still after eating

In a sentence about la siesta, many learners will hear it as after lunch, because siestas are traditionally associated with the midday meal.

Because gustar works differently from to like in English.

A useful way to think of gustar is:

• me gusta X = X is pleasing to me

So in this sentence:

• me = to me
• gusta = is pleasing

You are not the grammatical subject. The thing being liked is the subject.

That is why Spanish says:

• Me gusta el café.
• Me gusta leer.
• Me gusta hacer la siesta.

Using yo gusto would usually mean I am pleasing / attractive, which is a different idea.

Because the thing that follows and controls the verb is the infinitive phrase hacer la siesta, and an infinitive is treated as singular.

So:

• Me gusta hacer la siesta.
  because hacer la siesta is one activity

Compare:

• Me gusta nadar.
• Me gusta comer.
• Me gustan las siestas.
  here it becomes plural because las siestas is plural

Because hacer la siesta is the normal fixed expression in Spanish.

Spanish often uses a verb + noun combination where English uses one verb. Here:

• hacer la siesta = to take a nap / to have a siesta

You may also hear:

• echar(se) la siesta

That is also very common, especially in Spain. But hacer la siesta is clear, standard, and very natural.

Because Spanish often uses the definite article with routine activities or set expressions.

So hacer la siesta is the established expression, not normally hacer siesta.

This happens in many other phrases too:

• tocar la guitarra
• tener la razón
• ir al trabajo

The article is part of how the expression is usually said.

Because Después de comer is an introductory time phrase.

In English, we also often put a comma after an opening phrase like:

• After lunch, I like...

In Spanish, the comma is common and helps readability, but in short sentences it may sometimes be omitted in informal writing:

• Después de comer me gusta hacer la siesta en el sofá.

So the comma is natural and good style, but not always absolutely required.

Because en el sofá is the natural way to say on the sofa in Spanish.

English often uses on, but Spanish frequently uses en where English uses on for furniture or places:

• en el sofá
• en la cama
• en la silla sometimes, depending on context

Sobre el sofá usually means more literally on top of the sofa and can sound more physical or unusual. For normal resting or sitting, en el sofá is what you want.

They show where the stress goes.

• después is stressed on the last syllable: des-PUÉS
• sofá is stressed on the last syllable: so-FÁ

Without the written accent, Spanish pronunciation rules would suggest a different stress pattern, so the accent mark is needed.

Accent marks in Spanish are not optional decoration; they are part of correct spelling.

Yes. That sounds very natural too.

• hacer la siesta = to take a nap
• echarme la siesta = to take a nap, with a slightly more idiomatic everyday feel

The me in echarme matches the person:

• me gusta echarme la siesta = I like taking a nap
• le gusta echarse la siesta = he/she likes taking a nap

Both versions are correct. For learners, hacer la siesta is often easier to recognise and use at first.

It describes a general habit or preference.

Me gusta usually means I like in a broad sense, not just one single moment. So the idea is that this is something the speaker generally enjoys doing.

If you wanted to talk about a specific day, Spanish would usually use a different structure, for example:

• Después de comer, hice la siesta en el sofá.
• Después de comer, me apeteció hacer la siesta en el sofá.

So the original sentence sounds like a usual preference or routine.