the easy way is download the app on your phone,
"naver webtoon "
(you can search on google or your app store, but sometime the appstore hiding this app if you cant type hangul character for naver webtoon so the easy way to find the app, Google it [if still cant find the app on appstore on your smartphone])
well naver webtoon basically provide the raw for this webtoon but the song already attached there, and for the better of the "feel" hoho
okay, you can open this
https://www.youtube.com/playlist?list=PLkjPLF97QW0L62rAQAUDIhP0ocR7AIQ9G
this is playlist for lookism if you see it, dont be surprise of the real singer that look exactly like the art here .... enjoy lol
actually if you read the raw ver on naver you will hear the song they sang here...
http://comic.naver.com/webtoon/list.nhn?titleId=641253&weekday=fri&page=3
beter if you use the naver webtoon apps on playstore