>What is Next-Gen Shader?

Get it and read about it from here https://gumroad.com/l/qdgcK
It's free (set the price to $0) but feel free to support Hanmen as creator too as well
Make sure it's working correctly and you have familiarized with it first before going further

>How do I use these files included in this package?

You don't need to use all of them, pick one of two methods listed here

The card:
1) Copy the card to card directory (as you would do with HS2 cards)
2) Load the card in chara maker/studio
3) Turn on SSS or load any Graphics mod presets for next-gen cards

Texture Files (For Advanced Users):
1) Load the original card of this character or your custom card that used this character's face in chara maker
2) Open Head Material Editor, change the shader to "Hanmen/Next-Gen Face"
3) In "Nailmask" slot, import included .png file that has "mask" on its name
4) In "SubsurfaceAlbedo" slot, import included .png file that has "ssa" on its name
5) Change the body's shader as well with Material Editor, tweak them as you want etc
6) Turn on SSS or load any Graphics mod presets for next-gen cards
7) Save the card

Notes & FAQs
1) I noticed that neck seam is minimal in chara maker but can be more visible in studio depending on preset used

2) Changing uncensor in studio caused change in body skin color, no other way to fix than reloading the card

3) Q: Why this roundabout way? Some other head mods I know don't need this and compatible with the shader right away
   A: Because of the UV in my custom head does not aligh perfectly with default UV. Other modders may made their 
      custom head align perfectly with default UV that is good for maintaining compatibilty with default assets
      (such as make-up). However, I have my personal reason to keep the custom head's UV unmodified as much as possible
      even at the cost of compatibility in make-up and this next-gen shader

4) Q: I found new error
   A: Report to me and I'll see what I can do. However, I'm still not very familiar with how the shader works or 
      using material editor in-depth so I might end up as confused as you are.

5) Q: I have general question about next-gen shader
   A: If it's not related to my mod, it's best to ask community like Illusion-soft discord or to Hanmen himself