If your Nokia phone is designed to work with a GSM carrier (like AT&T or T-Mobile) it uses a SIM card to connect you to the network. The SIM card holds important information, such as names and numbers from your phone book. If you've stored contacts to your phone's internal memory, moving them to your SIM card backs them up and allows you to take your phone book with you when you switch devices.
Press the "Power" button to turn your phone on.
Press "Menu" and highlight "Address Book." Press "Select."
Scroll to and select "Copy Contacts." Choose "From Phone To SmartChip."
Choose "Yes" to confirm.