From main menu, select Settings and then Cellular.
Check that Cellular Data is turned on.
Tap Cellular Data Options and then Cellular Data Network.
(If this setting does not appear it cannot be configured manually. Please contact the seller.)
Go to Cellular Data and enter information as below
Go to LTE Setup (Optional) section and enter information as below
APN: (Leave Blank)
Username: (Leave Blank)
Password: (Leave Blank)
Enter the below details in MMS section:
MMS Proxy: 10.0.0.200
MMS Max Message Size: 1048576
MMS UA Prof URL: http://www.apple.com/mms/uaprof.rdf
Press the Home button to save the APN and exit to the main screen.
Restart the iPhone.