Upon first attempt to log into the Zoom Admin account, leave "Old Password" blank and type in a new password of your choice.
For more information on how to change Zoom Room settings, visit: https://support.zoom.us/hc/articles/-Changing-settings-for-a-Zoom-Room
For more information on Room Passcodes for Zoom Room, visit: https://support.zoom.us/hc/articles/undefined-Room-Passcode-for-Zoom-Rooms