Installing Mods Into Running Worlds

How do you install a mod in world that is already in progress? I seem to have done it before, but I can’t remember how. I was able to get the Cataclysm ++ (the one I’m using) mod into the game for use in world gen, but not in my actual world.

Into the world save dir, you have to manual edit MODS.JSON adding the “ident” of the mod in the list.