Notes
How to add a WiFi connection to NetworkManager from console
$ sudo nmcli con add con-name MyConn ifname wlan0 type wifi ssid MySSID ip4 192.168.1.100/24 gw4 192.168.1.1
$ sudo nmcli con modify MyConn wifi-sec.key-mgmt wpa-psk
$ sudo nmcli con modify MyConn wifi-sec.psk MyPass123456