>>328513289
>read up
no, just a bunch of amateur videos on youtube
but from what I've seen it basically consists of
>get clothes you want to fit, make sure it's rigged 
>align the clothes to fit your avatar by moving the armature, edit bones to fit as closely as possible
>if needed, enter sculpt mode to edit the mesh to fit better, use tools like grab or fill
>merge armatures, either with CATS or manually
>check weightpainting