눈 = eye(s) 들어오다 = come in
에 is one of Korean postpositions. Its meaning is mostly similar to 'at' and it's usually used after many nouns. If you turn away from the ground to the sky, twinkling stars and the bright moon would be reflected in your eyes. Actually you see them yourself, you can choose them as the subject and can say '눈에 들어온다 in an indirect way.
I saw twinkling stars and the bright moon. 나는 반짝이는 별들과 밝은 달을 봤다.
Twinkling stars and the bright moon came into sight. 반짝이는 별들과 밝은 달이 눈에 들어왔다.
A : Have you seen him in the movie?
B : No?
A : Why? He's so hot!
B : But his friend is so much hotter!
Anything else didn't come into sight. 다른 건 눈에 안 들어왔어.
자리매김 Being established
The woman's established herself as a great interpreter. 그 여자는 훌륭한 통역사로 자리매김했다.