Setting up PPP on the Pi/Ubuntu for use with MTQ, MTC, MTD, and other basic celluar modems

Commands (as root):
apt-get install modemmanager network-manager network-manager-pptp 
systemctl enable ModemManager 
systemctl enable NetworkManager
Reboot and confirm that modem manager is running and detected the modem using:
mmcli -L
Check the details of the modem (including that the SIM is detected, if relevant):
mmcli -m 0
(if 0 is the modem's number from the mmcli -L command) You should see state: 'registered'  in the "Status" section.
Create and bring up the connection:
nmcli c add con-name "dragonfly" type gsm ifname "*" apn "YOUR APN HERE"
nmcli c up dragonfly
Should see something like:
"Connection successfully activated (D-Bus active path: /org/freedesktop/NetworkManager/ActiveConnection/18)"

If that did not work check your APN.  Change it using:
nmcli c modify "dragonfly" gsm.apn "YOUR APN HERE"
Check that you have an ip address on wwan0.  You may need to run dhclient wwan0.