Learn Hardcore Korean: oneureun jibeseo swigo eumageul deureoyo. - Today I rest at home and listen to music.

오늘은 often implies a contrast like (not yesterday / not tomorrow).
If you used 오늘이, that would be the subject particle and would sound more like Today is (the one that)… in a subject-focused way.

What’s the difference between 집에 and 집에서? Why is it 집에서 here?

집에 marks a destination / where you are (exist), while 집에서 marks the location where an action happens.

집에 가요 = I go to home. (destination)
집에 있어요 = I’m at home. (existence)
집에서 쉬어요 = I rest at home. (action happens there)
Since 쉬고 and 들어요 are actions, 집에서 is the natural choice.

Does Korean need a subject like I or we in this sentence?

Not necessarily. Korean often omits the subject when it’s clear from context.
오늘은 집에서 쉬고 음악을 들어요 commonly implies I (or we) depending on the situation, but it doesn’t have to be stated.

What does 쉬고 mean grammatically? Is it “and,” “then,” or “while”?

쉬고 is 쉬다 (to rest) + -고, a very common verb connector meaning and (often and then, depending on context).

It can simply list actions: rest and listen.
It can also imply sequence: rest and then listen.
If you specifically want while resting, you’d often use 쉬면서 instead.

Why is it 음악을 with -을?

-을/를 is the object particle. 음악을 marks music as the direct object of the verb 듣다/들다 (to listen).
In casual speech, people sometimes drop it (음악 들어요), but 음악을 들어요 is clear and textbook-correct.

Why is “to listen” written as 들어요 and not something like 듣어요?

The dictionary form is 듣다 (to listen), and it’s a ㄷ-irregular verb.
When a vowel follows (like -어/아요), the ㄷ changes to ㄹ:

듣다 → 들어요
So 들어요 is the correct conjugation.

Is 들어요 present tense, or can it mean “I’m listening”?

In Korean, the plain present form like 들어요 can mean:

a general present/habit: I listen (to music)
a current action (depending on context): I’m listening (to music)
If you want to be explicit about “right now,” you can use 듣고 있어요 (listening right now / in progress).

Why does the sentence end in -요?

-요 marks the polite casual style (often called 해요체). It’s appropriate for everyday conversation with people you’re not extremely close to, or when you want to be politely neutral.
A more casual version would be 들어 (no -요), used with close friends.

What’s the basic word order here, and is it flexible?

The common order is:
Time (오늘은) + Place (집에서) + Verb 1 (쉬고) + Object (음악을) + Verb 2 (들어요)
Korean word order is fairly flexible because particles show roles, but the final verb (들어요) still typically comes at the end.

Can I drop 오늘은 or 집에서 and still have a complete sentence?

Yes. Korean often drops information that’s understood. For example:

집에서 쉬고 음악을 들어요. = I rest at home and listen to music.
오늘은 쉬고 음악을 들어요. = Today, I rest and listen to music.
쉬고 음악을 들어요. = I rest and listen to music. (context-dependent)