I wanted to see if the image I created could be set up headless but Windows won't recognize the card so there's no way I can see to add the wpa.supplicant.conf file before booting it on the Pi. The easiest thing would be to use an HDMI cable to connect to a monitor or TV and a USB keyboard (no mouse needed). Then you could power up and go through the wifi configuration. Once done, you can shutdown, remove the HDMI cable and keyboard and then power up with just the CM19a plugged in. Then you should be able to open HA-Bridge from a browser.