How to obtain
Currently, these Hats are random findings in Wood Treasure Chests, Stone Treasure Chests, Obsidian Treasure Chests, Iron Treasure Chests and Diamond Treasure Chests. They cannot be obtained in any other way. These chests randomly spawn on different layers of any Creativerse game world in dark places in a certain proximity around player characters. The ones on the surface Wood Treasure Chests only spawn at night though.
How to use
To dress up a Pet of yours (or Pets of other players that you are allowed to access), open the Pet window by using right-click or "f" (default key) while looking at the Pet, then click on any accessory that you have found and that you are currently carrying in your inventory (can't be placed into quickslots) to automatically move it into the correct accessory slot of the Pet.