APN Setting in EC-25

Hello Community,
We are establishing an Private LTE Network, We are using EC-25 modem but I’m unable to register EC-25 modem in our private network, As I understood to register any LTE Modem/Standard LTE Mobile need to set APN setting with customized MCC, MNC settings.

But I’m unable to set APN for the EC-25 Module, So kindly help me to do the same, as well In EC-25 how to enable VoLTE please guide me.