Every Natsuki expression
Natsuki comes with 39 face variations pulled straight from the game, covering blunt, easily flustered, the tsundere of the club.
Open the Expression tab and every face shows up as a thumbnail — you pick by looking, not by guessing at file names. Switch outfits and poses from the Pose tab: uniform and casual, a crossed-arms pose, plus the old-art and glitch looks.
Writing lines that sound like Natsuki
The text box fits three lines, and short lines read better at thumbnail size — something like "D-Don't get the wrong idea, okay?!" is about the right length.
The line counter above the input tells you when you're about to overflow, so nothing gets silently cut off when you export.
Put her in a scene with someone else
Tap "Add character" in the Character tab to put more people beside Natsuki — another club member, the protagonist, whoever — then snap them left / center / right, or use the sliders to move and resize each one.