~는 것, ~은/ㄴ 것, and ~을/ㄹ 것 allow you to transform action verbs into nouns. 것 means “thing” but in this context it can also mean “act." ~는 when attached to an action verb stem modifies the following noun. ~는 것 is present tense and thus suggests ongoing action. 사는 것 = buying, the act of buying, what you buy, the thing you buy 가는 것 = going, the act of going 듣는 것 = listening, the act of listening, what you listen to, the thing you listen to 공부하는 것 = studying, the act of studying, what you study, the thing you study In the following sentences, 것 is replaced with other more specific nouns. So ~는, ~은/ㄴ, and ~을/ㄹ modify the noun that follows, whether the noun be 것 or something else. 자주 먹는 음식은 밥이에요. The food I eat often is rice. 제가 사는 곳은 서울이에요. The place I live is Seoul. Also note that since ~는 것, ~은/ㄴ 것, and ~을/ㄹ 것 form new clauses, you must attach 이/가 to the clause’s subject if the subject of the clause is not the subject of the entire sentence. 제가 자주 만나는 사람은 미국사람이에요. The person that I meet often is American. 여자친구는 내가 자주 가는 나라에 가고 있어. My girlfriend is going to the country that I go to often. ~은/ㄴ when attached to an action verb stem modifies the following noun. ~은/ㄴ 것 is past tense and thus suggests completed action. 어제 먹은 음식은 너무 맛있어요. The food I ate yesterday was delicious. 지난 주말에 우리가 가지 않은 커피숍은 프라푸치노로 유명해요. The coffee shop we didn’t go to last weekend is famous for frappuccinos. ~을/ㄹ when attached to an action verb stem modifies the following noun. ~을/ㄹ 것 is future tense and thus suggests future action. 내일 읽을 책을 빌렸어요. I borrowed the book I will read tomorrow. 제가 갈 곳은 케나다예요. The place I will go to is Canada.

As saw in that answers 는 것 is the "~ing " but i didnt really understand when i should use it !

I'm not the best but I'll explain it as easy as I can. speaking of "change it to a noun", example is 'go' >> 'to go' or 'going', 'eat'>> 'to eat' or 'eating' so in korean, 'go' is 가다 which is verb and 'to go' or 'going' can be used as 가는 것 which is noun. you can put '~는 것' instead of '~다' in verb. example) 가다 >> 가는 것, 먹다 >> 먹는 것. if still confusing, feel free to ask