1. The battery and SIM compartment can be found on the bottom of the ZTE MF288. Slide the cover towards the front of the ZTE MF288 and lift up to remove it.
2. If the battery is already in the ZTE MF288, you need to remove it before inserting the SIM card. Place your thumb or finger in the small notch at the bottom of the battery compartment and lift up the battery.
3. Insert the SIM card with the metal contacts facing down. Slide it into the SIM card slot.
4. Line up the gold contacts on the battery with the contacts on the ZTE MF288. Insert the top part of the battery first, then push it into place.
5. Line up the cover tabs with the appropriate holes inside the ZTE MF288, and then slide the cover until it clicks into place.