About custom faces and characters presets

[vocal]

Greetings!

I've recently been reading some threads about character face presets but didn't find anything about what i'm looking for.

 

From what i understand, modders like GomaPero that have (at least in my opinion) beautiful character presets don't only use the tools found in racemenu/ECE, correct? 

Correct me if i'm wrong but it seems, they are able to import character head models (or at least partially) from other games into skyrim, and then model them accordingly.

With a quick google search, is easy to find head models, like this one from the DOA girls https://www.deviantart.com/xps-fanatic/art/XNALara-Fanatic-s-Head-Stash-Female-Version-659423227

But is there any tutorial on how would i import these to skyrim?

If not, could someone point me in the right direction? (Assuming i'm not completely mistaken in my assumption on how these modders create their presets)

Thank you!