Microsoft Lumia 640 XL LTE User Manual page 8

Do not use any tools, as they may damage the phone.
3. If the battery is in, lift it out.
4. Slide the micro-SIM card into the SIM slot with the metal contact area down.
5. If you have a memory card, push the card into the memory card slot.
It is recommended that you use a fast microSD card from a well-known manufacturer.
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