Before inserting and taking out the SIM card, always make sure that the
phone is switched off and disconnected from any external power source;
otherwise both the phone and the SIM card may be damaged.
3.2.2. Installing and uninstalling the SIM card
The SIM card usually comes attached to a special card. The metal contacts of
SIM card is easily damaged by scratching, so take it out carefully before
assembling it into the phone.
Switch off the phone; remove the back cover, battery and other external
power source. Fit the SIM card into the SIM card slot. Align the angled corner
of the SIM card with the slot. Slide in the SIM card, make sure it is in place,
install the battery, and restore the back cover.
Likewise, to remove the SIM card, switch off the phone, remove the battery
and then take out the SIM card.
3.2.3. Unlock the SIM card