Johnex
28
Well that is how far you will get from the GL-iNet interface.
Now it’s time to go deeper 
If you are on windows download Putty. Run it and connect using SSH to the router IP, while you are connected to it with Wifi or Lan 
Username is root, password is the password you set for the Web interface.
Run this command first:
uqmi -d /dev/cdc-wdm0 --get-data-status
It will say “disconnected”. Then:
uqmi -d /dev/cdc-wdm0 --get-signal-info
It should say some signal values. If not tell me what it says. If yes, then do:
uqmi -d /dev/cdc-wdm0 --start-network internet --autoconnect
The “internet” in the command is your APN.
Lastly:
uqmi -d /dev/cdc-wdm0 --get-data-status
It should say “connected” hopefully 