As far as I know, the stun servers are just there to try and obtain your computer's (external) IP address, ususally you would just ignore them as they should not affect the operation with different service providers.
When you set up your Peopletelecom account with Axon you will be given a number, password and a server.
Your settings should be like this:
Friendly Name: Anything you wish, can also be used for caller ID sometimes
Username: Your username of more likely the number Peopletelecom gave you
Password: The password provided by Peopletelecom
Server: Peopletelecom's SIP server. Usually its in the form of sip.peopletelecom.com, but this is unique for each service so check with them / the instructions they give for the server address.
If you are unable to locate some of these settings, you can try to open the Grandstream configuration page and obtain the settings from there.