Ending Act One
How do you know when Act One is done? To be honest, these terms we use are as flexible and fluid as the stories we tell. Generally, the first act should take up somewhere between 15-20% of your overall story. It’s often shorter than the second act, and longer than the final act. It needs to set the stage, and once you’ve established all of the above — your protagonist and their ordinary world, what they desire, what’s at stake, the tone, and the inciting incident — then comes the final element. The protagonist’s decision to cross the threshold and take action. They may refuse the call at first, but they must have the agency to decide to continue and face the consequences of failure.
Then you’re ready to move on to Act Two… which is where things really get interesting.