You aren't dumb but that's neither a trivial task you would need to abstract a good portion of the current quest system into something user friendlier than writing some blueprints and try to get just that part of the blueprint functions out to the user in form of some external editor.
Do you know any Unreal project that ever released a Mod Editor
?
In terms of Unreal you have also some Licensing Hurdles in front of you Epic wouldn't like that
You can rewrite Unreal but in General you aren't allowed to distribute the modifications of Core Engine Parts or UI except they running in the Engine Itself.
It's quiete a complex Lawyer Minefield with Unreal.