To edit the title of your video, please follow these steps:
Go to the "My Stories" tab.
Locate your video in the list.
Tap on the three dots menu icon.
Select the option "Edit title."
Edit the title of your video as desired.
Tap on "Go" or any similar confirmation button to save the changes.
By editing the title, you can easily identify recordings of the same book for different children or any other purpose you have in mind.
Here is a video that shows it.