OpenGameArt.org
Ocean Planet
Credit line
"Ocean Planet" by onemansymphony licensed CC-BY 4.0: https://opengameart.org/content/ocean-planet Author's attribution notice: Composer: İlker Yalçıner (ilkeryalciner.com)
Where to put it: Game credits or video description. If the entry has a "Copyright/Attribution Notice", follow that.