Humanoids are not physical classes(You cant see humanoid in the world like parts,trusses,meshes) and a sound need an origin(vector3 position) so it will make sense to parent the sound to your weapon handle or whatever part there is, but if you insist in adding it then add it to the humanoidrootpart or any physical part
As @builderIV said, parent it to the HumanoidRootPart, but also don’t forget to navigate from the tool to the actual Character in the workspace, not in the Player folder in the workspace.
The Player is (basically) where your avatar gets loaded into the game, so it won’t play any sound you have in it because it’s just in storage.