Trouble accessing internet

Hi all .

Ive just bought a smarty data only sim and set up an unlimited account, I’m trying to use it in a generic LTE 4g usb modem with wi-fi hotspot in a caravan.

I put the sim in after getting conformation of account , plugged it in and it’s showing a led with red and blue colours on it and I can’t find anything in my phone wi-fi settings.

After searching online I managed to use a laptop to go into the modem settings to change the apn settings to smarty. But nothings made any difference to the lights or being able to find it on my phone.

can anyone help please ?

Thanks , Adam