Learn Hardcore Korean: hyuire gajokgwa hamkke jibeseo yeonghwareul bwayo. - On holidays, I watch movies at home with my family.

In Korean, 에 marks a specific point in time when something happens. Here, 휴일에 means “on holidays.” You use 에 after time words (like dates, days of the week, holidays) to say “at,” “on,” or “in” that time.

What does 가족과 함께 mean, and why use 과 instead of 와, 하고, or 랑?

가족과 함께 literally means “together with family.”

과 attaches to nouns ending in a consonant, 와 to those ending in a vowel.
하고 is more colloquial and neutral (“and/with”), 랑 is very informal.
함께 adds the nuance of “together,” so 가족과 함께 is slightly more formal/polished than 가족하고 같이.

Could we use 같이 instead of 함께, and is there any difference?

Yes. 같이 also means “together.” Differences:

함께 is a bit more formal or literary.
같이 is colloquial and very common in spoken Korean.
Both are correct:
• 가족과 함께 집에서 영화를 봐요
• 가족이랑 같이 집에서 영화를 봐요

Why is 집에서 used here, and why not 집에 or 집으로?

에서 marks the location where an action takes place. So 집에서 means “at (in) home,” indicating the place of watching.
집에 would mean “to home” or simply “at home” in a static sense (existence, movement).
집으로 means “toward home,” so it’s about direction.

Since you’re doing the action (watching a movie) at home, you need 에서.

What is the role of 를 in 영화를?

를 (or 을 after a consonant) is the object particle. It marks 영화 as the object of the verb 보다 (“to see/watch”). So 영화를 봐요 means “(I) watch a movie.” Without it, the sentence would be unclear about what is being watched.

Why is the verb 보다 changed to 봐요 here?

봐요 is the polite present tense form of 보다:

Remove 다 from 보다 → 보
Add 아요/어요 ending. Since ㅗ in 보 is a bright vowel, you use -아요, but two vowels contract: 보 + 아요 → 봐요.
The -요 ending makes the sentence polite and suitable for most everyday conversations.

Why is the subject omitted in this sentence? Who is doing the action?

Korean often omits the subject when it’s clear from context. If you and the listener know who is talking about, you don’t need to repeat 저는 or 우리는. Here, the implied subject is “I” (저) or “we” (우리) depending on context. Adding 저는 or 우리는 at the start is possible but not necessary for clarity:
• (저는) 휴일에 가족과 함께 집에서 영화를 봐요.