Hello, sorry to bother anyone but am having problems with some skill books that I got, where do I need to go in order to learn that skill? Thank you.

If they are morai or 79/99 skills, go to your master trainer (City of a thousand streams)

Isnt 99 (100) skill books can be learned only in demon/sage world depending from your cultivation?

the books are not demon nor sage, am a barb, one book is called Slam "more power then slam level 10" and the axe & hammer mastery "more powerful then axe & hammer mastery level 10" I tried my barb trainer but he couldn't do it.

They are level 11 skills, which are by default sage or demon. Does it have a ○ or • in front of it? Are you sage or demon? ○ Is sage you need to go to heaven for that. • Is demon, you need to go to hell for that. The skills need to match your culti, you cannot be sage and learn demon skills.

Uh • is sage and ○ is demon. Anyway, check the cultivation required. Maybe you are Aware of void/myriad and the books require Master of Harmony/Discord or Celestial Sage/Demon.