How do I insert my SIM card?
Please follow below steps to insert the SIM card into the One:
1. Use the ejector tool that came with your OnePlus One to remove the SIM tray.
2. Put the Micro-SIM card in the SIM tray and make sure the card is flush with the edges of the tray.
3. Carefully make sure the SIM tray is inserted correctly, right side up, with the contact (gold part) of the SIM card facing the back side of the One. If you are using a Nano-SIM, please be aware that some adapters might damage the motherboard of the One, which is not covered by warranty. We highly recommend that you get a Micro-SIM card from your mobile operator.
4. Make sure your SIM tray is fully inserted and flush with the side of your One.