Mystic in the codex

How do you unlock them?
Do you have to do what it tells you or do you make the combo with stones? And what does it do if you do unlock them?

Wiki . go to codec on the wiki an you will find the info that you need for your mystic enchantment

You randomly unlock those by socketing any mythstones. It’s not like this is supposed to be secret anyway, so might as well go to the wiki for the recipes