Before you start using Screen Time and the "Always On Downtime" method, make sure your child's iPhone is set up correctly under your Apple Family.
On your iPhone:
Settings → Your Name → Family → Add Member → Create Child Account (or invite them if they already have an Apple ID).
Follow the prompts to add your child to your family group.
✅ Make sure your child appears in your Family list before moving on.
On your iPhone:
Settings → Family → Select your child's name → Screen Time
Tap Turn On Screen Time.
Choose This is My Child's iPhone when prompted.
This is the most important step.
When asked to create a Screen Time passcode:
✅ Use a code your child cannot guess.
✅ Make it different from: