You need to activate your mobile phone before using it for the first time and also when you've restored the factory default settings. You need to insert your SIM card and turn on your mobile phone before using it for the first time. You also need to install iTunes on your computer. You can download the program from www.itunes.com
Enter your PIN
Key in your PIN and press OK.
If your mobile phone rejects the SIM card:
Contact your distributor or service provider where you bought your mobile phone.
If you enter an incorrect PIN three times in a row, your SIM card will be blocked.
Connect mobile phone and computer
Start the program iTunes on your computer.
Connect the data cable to the phone socket and to your computer's USB port.
Activate your mobile phone
If it's the first time you activate your mobile phone:
Follow the instructions on the screen to log on using your Apple ID and activate your mobile phone.
If you've used an iPhone before and have backed up the phone memory using iTunes, you will, during the activation process, have a chance to restore an iTunes backup.
When the activation is complete, the screen shows that your mobile phone is ready for use.