I'm sorry to say goodbye. Life is a wonderful thing and unfortunately, i haven't known you for a long time but it's still sad seeing you leave. Do whatever you think will make you happy, the whole community will support you regardless!
Ok so I will delete some posts just bc it's more pleasant with one, my first question is where you obtained the files and the second thing is that the world is in survival, if you want to explore it in creative just press esc, press open to LAN, switch to creative and lastly press start LAN world.
Edit: I don't know how to remove the posts, i reported them and hopefully they will get removed!