1. When the SIM card is missing, the Missing SIM icon will display in the Notification bar. 
   
2. To access the Nano-SIM card and microSD card slots, remove the back cover by pressing a fingernail in the notch on the bottom center of the device. 
   
3. To remove the back cover, hold the phone firmly in one hand. With your other hand, lift off the back cover with your thumbnail.
   
4. Remove the battery. 
   
5. To insert the SIM, insert the Nano-SIM card with the metal contacts facing down into the SIM slot. To remove, simply slide it down.
   
6. To insert a microSD card, insert the microSD card with the metal contacts facing down into the microSD card slot. To remove, simply slide it down.
   Note: A microSD memory card (Sold separately) expands storage capacity of the device. A microSD card up to 2TB can be used. To prevent data corruption, it is recommended to unmount your memory card before removing it. To unmount your memory card, tap Settings > General > Storage > Unmount SD Card.