Mo Creatures for Minecraft?

Added (1). I want to get mo creatures for minecraft, but according to my sister you have to delete all your current worlds in order for it to work? Is this true? And if so, is it possible to save them?

Emily 11.07.2015

No. Not true at all. No idea where she got that from. Just watch this tutorial, it should help you out.

Also, open "run" type in %appdata%/.minecraft. This will lead you to your minecraft files, just copy the saves folder and paste it in your desktop and all of your worlds will be saved. If your worlds ever happen to be deleted, just replace the saves file with the one from your desktop.

Jonathan 11.07.2015