Back up your iPhone to iCloud or a computer (if you haven’t already)
Plug the iPhone into power
Connect the iPhone to Wi‑Fi (or keep it connected to your computer)
Turn on the iPhone and start the setup screens
On the setup screen, choose your language and region
Select your Wi‑Fi network
When asked how to set up iPhone, choose Restore from iCloud Backup or Restore from Mac/PC
Sign in with your Apple ID
If restoring from iCloud: choose the backup to restore from, then wait for the restore to finish
If restoring from computer: select the device in Finder (macOS) or iTunes (Windows), then choose Restore Backup and pick the backup
Keep the iPhone connected and do not sign out of Apple ID during the restore
After the restore completes, finish setup (Face ID/Touch ID, passcode, and settings)
Wait for apps and data to finish downloading (if applicable)
Verify the backup restore by checking photos, messages, apps, and settings