OpenGameArt.org
Singing In The Rain (Guitar)
Credit line
"Singing In The Rain (Guitar)" by Pro Sensory licensed CC0: https://opengameart.org/content/singing-in-the-rain-guitar Author's attribution notice: please include my name in your project's credits, Alex McCulloch.
Where to put it: Game credits or video description. If the entry has a "Copyright/Attribution Notice", follow that.