Hey man! Thank you so much, I'm happy that you're enjoying the game
Answering your question: man, it's kinda hard to talk about this because it's very subjective. What would "Ana in action" be?
For many, the action already started back in Chapter 01, when Ana appears with Max
And for many others, the action will only start when she has her first penetration with another man
Personally, I consider the starting point the moment Ana lets the MC grab her boobs in front of everyone, exposing an intimacy (Chapter 03)