The safest option now is to file a maintenance request ticket and wait for the reply. This is the only thing I can truly recommend.
However, if you really want to try to resolve it yourself, risking a possibly bricked or otherwise beyond self-repair device, here’s what I believe are the steps. I did not actually make it to the all-good state, so this is partly based on my understanding of what other people reported.
- Fully charge the battery.
- Boot. Plug a USB mouse.
- Use the mouse to go through the wizard.
- If you are lucky like @carepack, the wizard will let you set up a security code. If you are unlucky like me, the wizard ends before you are able to set a security code. Either way, you should be in the main lockscreen now with the clock visible, or directly at the desktop.
- If you have set up a security code and wlan, it may be ok to reboot, based on reports. Otherwise, keep the phone on and charged until further instructions are available.
- If security code, encryption or wlan is not setup you could possibly try to access the settings app and set them up from there. I didn’t see anyone reporting they tried or managed to do this or if it would be ok to reboot after that.