OpenGameArt.org
Super HelmKnight OST - 16-bit (Game Boy Advance style)
Credit line
"Super HelmKnight OST - 16-bit (Game Boy Advance style)" by wyver9 licensed CC-BY 4.0: https://opengameart.org/content/super-helmknight-ost-16-bit-game-boy-advance-style Author's attribution notice: credit me as @wyver9 (also you can add link to my Twitter or Bandcamp)
Where to put it: Game credits or video description. If the entry has a "Copyright/Attribution Notice", follow that.