Turn on your iPhone and follow the setup steps until you reach the Apps & Data screen
Tap Restore from iCloud Backup
Sign in with your Apple ID
Choose the backup you want to restore
Stay connected to Wi-Fi and power until the process finishes
If restoring from a computer, connect your iPhone to the computer
Open Finder on Mac or iTunes on Windows or older Mac
Select your iPhone
Click Restore Backup
Choose the correct backup
Enter the backup password if required
Wait for the restore to complete and keep your iPhone connected
Finish the setup process after the restore is done