I agree with OP - a newbie who has never tethered a BT/DUN phone is kinda overwhelmed by it all and no place for help in troubleshooting, tips, tricks, ideas, workarounds, which phones work etc. There are some who do not realize that the phone must actually be BT.

I have had to re-tether because of upgrade/flash once and again because of a reset and either time didn't back-up - just didn't know. I still really have no idea what I am doing when I am pairing the devices but it seems to work each time.

I vote for the phone forum.