Power off the device by unplugging from the power outlet.
If a SIM card is already installed, remove the existing SIM card found on the left hand side of the modem by pushing to release the SIM card and remove it.
Insert the new SIM card on the left hand side of the device with the gold plated part of the sim card facing up and the wedge (notched out part of the sim) toward the modem until you feel it click into place.
Power your modem up and give it about 5 minutes to power up. This should restore your internet service.
Check out the Mofi4500 unboxing, sim card insertion video below!
Mofi4500-4GxLTE SIM CARD INSTALLATION