If you still needs help for it.
Create new world add Magiclysm mod.
It’s at the end of the list.
Or you can add it manually by editting “Your CDDA folder” > save > “Your intended world” > mods.json. Add the mod id you wanted in this case “magiclysm”. Be careful every mod id should be closed with quote sign and ended with comma except the last mod id. It will look somewhat like this.
[
“dda”,
“others_mod_id”,
“magiclysm”
]
Now you can play with magic.