Every Sayori expression
Sayori comes with 29 face variations pulled straight from the game, covering cheerful on the surface, which is exactly why her sad faces hit hard.
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 clothes, plus the old-art and glitch styles.
Writing lines that sound like Sayori
The text box fits three lines, and short lines read better at thumbnail size — something like "Do you want to walk to school together?" 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 Sayori — another club member, the protagonist, whoever — then snap them left / center / right, or use the sliders to move and resize each one.