In these early ten pages of the screenplay, which equals the first ten minutes of the movie, the audience must be introduced to, and made to empathize with, or connect to, or identify with, the protagonist in some way.
The audience MUST be made to CARE whether this guy or gal lives or dies, or wins or loses, or succeeds or fails.
Otherwise, the Reader wants to stop reading by page ten, not caring what happens to your major character.
And the moviegoer, should the piece ever make it to the screen, leaves the theater (at least mentally) ten minutes in.
Because the through-line of the story is going to be about this guy or gal trying to achieve a goal, or get somewhere, or get something, or maybe get someone. And if you, the writer, don’t get the audience to care whether your protagonist succeeds or fails at his/her quest, and get them emotionally connected to him/her, then they won’t be inclined to stick around to see what happens.
They simply won’t care.
And by the end of page ten, we should also have experienced an incident that incites; in other words, kicks off the protagonist’s journey.
Whether the inciting incident is of the protagonist’s own making or due to an outside influence doesn’t matter – what matters is that there is one.
In short, you’ve got ten pages which equal ten minutes of screen time to “hook” your audience.
So it’s a very good idea to use those ten pages wisely.