Galasstickus

Can someone please made a tutorial about how works FvTwool. I read it this https://metalgearmodding.fandom.com/wiki/FMDL, this https://metalgearmodding.fandom.com/wiki/FV2 and https://unknown321.github.io/mgsv_research/fv2.html but still I don't understand nothing how attach models to the head like glasses berets and other things, and I want learn how do multiple camo like this mod https://www.nexusmods.com/metalgearsolidvtpp/mods/774