Hello victoria9066 ,
Dashboard -> Online store -> Customize -> Slideshow
from here you can customize your store and add Text overlay
This might be irrelevant to this post but I can't find the answer anywhere else. We are trying to use the narrative theme's default "video with overlay text" section, the overlay text is underneath and not overlaying.... I'm not sure what's wrong.. If anyone knows what's wrong or how to fix this.. that'll be great!!