We need to make sure provide correct telnet/ssh credentails in Devices>manage, Airwave uses SSH credentials to take controller/switch config_backup.
Default Airwave take device config backup every night and on demand we can manually take device backup from Device>config page also Airwave take device backup automatically if it noticed any config change on controller/switch.
We can check all device config backup files in Devices>config page. Airwave nighlty backup file will include this files aswell.