Sorry for the confusion, but the fountain graphic is located in the 'img' folder under 'characters'. The file is named '!Ch_Other2.png'. To apply it as shown in the demo scene, it is convenient to use the prepared common event. (For RPG Maker MV) You can use the 'Water Fountain' common event by overwriting the 'CommonEvents.json' file in the 'data' folder within the 'MVdata_En' folder inside the '00_project' folder to your project's 'data' folder. However, if you have already set various common events, overwriting might cause issues, so it might be better to create a new empty project and overwrite the 'img' and 'data' folders as a whole, so you can refer to various things from there.
I'm not sure if I explained it well, but if you have any questions, please feel free to ask.