Determiners are particles attached to nouns in order to determine their function in a sentence, often denoting subjects and objects (direct and indirect). Determiners in Korean are slightly dependent on the final sound of the noun.
~는/~은 are the particles used to determine the subject of a sentence, or the one doing the action. "~는" is used whenever the final sound of a noun is a consonant, while its converse, "~은" is used whenever the final sound of a noun is a vowel.
E.g.(저는 지베 갑니다.) Literally: I (subj.) house to-go.
~를/~을 are the particles used to determine the direct object of a sentence. "~를" is used when the final sound of a noun is a vowel, while "~을" is used when the final sound of a noun is a consonant. E.g( 저는 나예 숙제를 하겠어요.)
Literally: I (subj.) my homework will-do.
~에게/~한테 are often used to determine the indirect object of a sentence. Despite both being grammatically correct, ~한테 is used far more often, as ~에게 is sometimes deemed as "too formal" in many situations.
E.g (저한테 그 책을 주세요.) Literally: I (in.obj.) that-book give.