There is a settings file template called settings.ini.example. You can specify the download directory with download_dir. Pressing the download button only downloads the song/album/playlist. If you set use_mpd=True in the settings.ini the backend will connect to mpd (localhost:6600) and update the music database. Pressing the play button will download the music. If use_mpd=True is set the mpd database will be updated and the song/album/playlist will be added to the playlist. In settings.ini music_dir should be the music root location of mpd. The download_dir must be a subdirectory of music_dir.