Find them on 유튜브 and use Freemake Video Downloader to download, the use Switchsound File converter to covert the video to an mp3 sound file, the put it on ur mp3 player.
just go to mp3 download sites and type in the name of the 아니메 i usually use mp3raid i get all my vampire knight songs from there 또는 go to catch video.net and convert the 유튜브 file into a mp3 format(just audio)