Don't attempt to remove the SIM card while the device is powered on. Doing so may harm the SIM card and/or the device.
Ensure the device is powered off.
From the left edge of the device, remove the card tray.
Utilize the insertion/removal tool (it comes in the box with the device) to unlock the tray by inserting it into the provided slot then remove the tray.
Remove the SIM card from the card tray.
If applicable, refer to Insert SIM Card.
Insert the card tray.
Press in on the tray to lock it into place.