Back up your old phone
Charge both phones
Connect both phones to Wi-Fi
Turn on the new phone
Follow the setup prompts
Choose to restore from backup
Sign in with your Apple ID or Google account
Select the most recent backup
Transfer contacts, photos, messages, and apps
Use a cable or wireless transfer if prompted
Insert your SIM card or activate eSIM
Check that all data transferred correctly
Reinstall any missing apps
Sign in to important accounts
Turn off the old phone after confirming everything works