OpenGameArt.org
Piano hip hop tune
Credit line
"Piano hip hop tune" by Rami99 licensed CC0: https://opengameart.org/content/piano-hip-hop-tune Author's attribution notice: you can use it as you want, if you mentioned me it would be cool but you don't have to.
Where to put it: Game credits or video description. If the entry has a "Copyright/Attribution Notice", follow that.