you have a couple of options to find it inet which is the default network interface and it has been set its subnetmask /24 which corresponds 255.255.255.0 by default. You can check it both linpeas and ifconfig command. The point that you are missing is first you cannot give default gateway address which is 192.168.1.1 by default on wlan0. Moreover, I assume that you have a failure on wpa_supplicant & wpa_passphrase configuration errors. Check them again and try again. I will also attach a list of commands that you need to apply correctly. The main thing that you need to understand is that we are managing wifi interface on linux environment.