What's the best blender tutorial for converting models?

Found this guy on deviantart called Vlthar who has a bunch of free video game character models. I liked some of the ones I saw and decided to try my hand at converting them into cc outfits in blender. The first roadblock I came across was that the materials that came with the models wouldn't link with the objects, apparently they don't have a node so it comes up as a blank when I try to select it.

I'm very unfamiliar with how to use Blender, the most advanced experience I have is crudely editing pre-existing hairs. Are there any beginner-friendly tutorials for converting models into CAS cc? Thanks.