So I seen some tutorials on how to use Blender and Sims 4 Studio and I understand some of the basics; but does anyone know a good tutorial on converting clothing from other programs or games for Sims 4?

I seen some amazing things people done using blender, MMD, XSP and other similar programs that creates models, poses, etc...but I can't find a good tutorial that is easy to understand (the few I found often has no speaking and some of the programs were in another language which made it hard to understand or follow). I want to make some custom cc for some of my favorite characters; but not sure how to really go about it.