I have update my connection to fiber connect ability. The royter/modem I take from the my company automatically connected but the to link not. Need to change something? I change the isp from adsl to v

1) I want to update my filmware. Which is the correct way to updated? 2) My modem have USB for 3g/4g adapter If I buy one from the net, automatically all phone in my house get extra signal from 4g?