Almost any character in a work of fiction will be representative of some universal human archetype, which is a shortcut authors use to hint to the reader what behavior they can expect from that character (or surprise them by subverting that expectation). Because we don't get into the deep life stories of every character who appears on the page, we have to signal to the reader through emotional cues and dialogue "what this character is like."
This could be anything from having a character behave like a precocious Mary-sue or a dashing, rogueish space captain, to the much simpler indicators that tell us "this guy tends to get angry a lot and be surly" or "this lady is bubbly and competitive."
If you want to get your character personalities right when TextSpark helps you write your scene, you have to establish some of these archetypal traits in your preceding text to clue it in just like you would a reader.
This is done via either nonverbal emotional signaling or dialogue. You may not be able to establish a complete personality in this space, but you can give the AI a sense for how each character talks and acts as a shorthand for their personality (or their emotions in this scene) and fill in more details later.
Example (continued from Scene Priming):
A man and woman who get into a fight might both be headstrong characters who believe they're right about a conflict from a previous scene. If you don't hint at these traits in your previous few hundred words, TextSpark won't know that about them and it might suggest behaviors for them that don't fit their characters.
By including a fiery dialogue exchange back and forth in the text before you want the AI to generate more, you can show TextSpark how each of these characters are willing to speak up and stand their ground, leading to the inevitable conflict escalation you're looking for, because it knows what "normally" happens when you put two headstrong people in a room and make them fight.
However, even within character archetypes and with a specific conflict, there are lots of different ways for a scene to progress. This is where our next tip, "Word Herding," comes into play.