OpenGameArt.org
Christmas Eve (Celeste version)
Credit line
"Christmas Eve (Celeste version)" by SoundSpect licensed CC-BY 3.0: https://opengameart.org/content/christmas-eve-celeste-version Author's attribution notice: "Christmas Eve" Composed by Michael Spect (www.soundspect.com)
Where to put it: Game credits or video description. If the entry has a "Copyright/Attribution Notice", follow that.