You can set up a Study routine so that your child will have a dedicated schedule for studying. Moreover, you can set the Break time rules to 'Study' if you don't want your child to use their device for any other purpose than studying.
To set up the Study routine, follow the ‘What are Routines, and how do I set them up on Superr?’ guide.
To configure Break time rules, follow the guide 'What are break time rules? What is downtime, free time and study?'