Working together with Nexus Mods, CD Projekt Red have come up with a new Mod Kit for The Witcher 3.
The kit allows you to meddle with the game’s world and follows many other separate mods (which won’t work with the new kit). There are also 4 mods built with the new tools and which are also downloadable from the site. These act alongside the tutorials to help you get to grips with modding the game.
You can grab both the Mod Tools and the new Mods from this site.