I'm trying to port the whole mod 1.16.5 to version 1.12.2 but there are parts in 1.16.5 where I don't understand how you did to change the state of the declarations such as CRITERIA that is in the AdvancementTriggers.class class since this is a private attribute. If you could give me an explanation on how to take it, I would appreciate it

You should not be trying to backport this project.

Ok, but i want to try, thanks