If you have connected the drive on the network using a router, I would reccomend you to go to your router webpage ( usually 192.168.1.1) and see list of devices connected under STATUS / WAN. You can see the IP address of all the devices connected to your network there.
Find the IP address of the WD drive, type that IP Address in your browser. It will take you to the login page of the WD drive. type in admin / admin as login and password.