Rules are easier to follow when children understand the reason, adults model the same habits and the family reviews what is and is not working.
Start with shared goals
Agree what devices are useful for and what sleep, school, play and family time need protection.
Make boundaries observable
Define where devices sleep, when notifications pause and which apps or contacts require adult approval.
Create a safe reporting route
Children should know they can report frightening content, contact or mistakes without losing support.