The Missing SIM icon will be displayed in the Notification bar when there is no SIM card in the device.
REMOVE BACK COVER & BATTERY: Remove the back cover by inserting your thumbnail into the notch at the bottom right of the back of the device and lifting up. Remove the battery by gently pulling up from the notch on the bottom.
INSERT/REMOVE SIM CARD: The SIM slot is above the battery compartment. Insert the Nano-SIM card into the SIM slot with the metal contacts facing down and the notched edge going in first. Push until it is all the way in. To remove, simply slide it down.
INSERT/REMOVE MEMORY CARD: Insert an optional MicroSD cardup to 32GB into the MicroSD card slot, with the metal contacts facing down and the notched edge going in first. Push until it is all the way in. To remove, simply slide it up. Note: MicroSD cards are sold separately. To prevent data corruption, it is recommended to unmount your memory card before removing it. To unmount your memory card, select Settings > Storage > Eject icon beside SD card.
REPLACE BATTERY: Place the battery in the battery slot with the gold contacts on the battery lined up with the gold contacts on the phone.
REPLACE BACK COVER: Place the cover on the back of the phone, then gently push in until the cover clicks. The cover should be flush with the rest of the device.