Learn how to manage SIM messages on the Nokia Lumia 521.
- Power the phone off.
- At the top of the phone, put your thumbnail in the seam between the screen frame and the back cover. Press the middle of the back cover, and bend the cover to loosen the top hooks.
- Press and bend the bottom part of the back cover to loosen the side hooks, and remove the cover.
- Lift the battery out using the notch located at the bottom of the compartment.
- Insert the SIM card.
- Replace the back cover.