Yea, latest BetterRepack is the way to go, it has huge asset library(items, effects, maps etc.) and tons of mods which greatly expand functionality of Charastudio or just add QoL tweaks.
Then look up some basic tutorials on youtube how to pose with FK/IK, use shadows/light, add accessories, how to parent. Then some slightly more advanced stuff like Material Editor, custom textures, shaders, gimmicks(pistons rotators etc.).
Finally advanced features like utilizing NodesContraints and Timeline to create awesome custom animations.
Charastudio has potential to create amazing scenes but there is definitely a learning curve.
Tbh you probably won't even need advanced stuff - most of the KK games here are very basic, devs just use premade animations and copy/paste assets without even tweaking textures or shaders...
Look at CK(Corrupted Kingdoms), dude makes thousands of $ and almost whole content is copy/pasted