AT+DEFMODE command, (and other AT Commands)

Hello,

I'm working on the I-NUCLEO-LRWAN1 LoRa expension board.

I succesfully build an application PingPong for this board. It is working fine. (Two module communicating!)

To understand better what is done, I would like to check the AT commands send to the modem.

There is an AT+DEFMODE, but I could not find any documentation about this. Where to find this documentation? And all other commands that can be send to the module?

Thank you

Antoine