Go to your PBX interface: pbx.mixpbx.net. Enter your logins : username and password.
Access the Extension section. Add a new extension.
Number Enter the number you want to assign to the phone (except 112 (ambulance) and 113 (police)). Mac Enter the Mac address that's written on the back of the phone (begins with 000413xxxxxx). Apply and do not forget to PUSH the configuration.
Go to the Configuration section and copy the provisioing link.
When you've copied the provisioning link, go to the phones Webinterface. Acces the Webinterface of your Phone by entering the IP address in your Browser (how to get the IP address). The default logins (if the phone is not yet configured) are username: snom password: 22222.
Click on Advanced (1) then Update(2).
Update Policy select Update automatically (3).
Setting URL Paste the provisioning link (4).
Apply and reboot