Downloads songs directly into your Geometry Dash music folder.
Enter the Song ID — the number from the Newgrounds audio URL:
newgrounds.com/audio/listen/1234567
^^^^^^^
Downloads the song and saves it so GD can find it by that ID.
Enter a YouTube URL and a Song ID of your choice (any number not already used by GD).
Downloads the audio, converts it to MP3, and saves it under the ID you provided. Use that same ID inside GD to play it.