first we will go to monitor mode

airmon-ng start wlan0

now we can scan for access points availble

airodump-ng mon0

now with this command we will start listening.

airodump-ng -c 11 -w myfile --bssid (the bssid) mon0

-c is for channel -w for file -bssid for router's bssid and our network interface
we will wait until we captured the handshake