“Unleashing the Beast: The Secret Strategies to Ignite Your Monster’s Motivation!”
In Act One, there is going to be some sort of awakening or reveal. Often this may even be the opening scene, it’s a moment that tells the audience THIS THING IS REAL. You’ll want to revisit this in another dozen pages or so when your main character gets their first clue that something monstrous is at play.
The first half of Act Two is all about the monster building its presence in the story. The speed and pacing vary greatly on the paradigm, type of monster, type of horror movie, etc. But generally, you’ll be building scares, each one a little bigger than the last. Keeping your paradigm in mind should give you an idea of how to go about this.