Octoplus Power up and Power down sensors and events

I have just discovered the Octoplus Power up/down sensors/events. I’d like to change my automations/scripts to use these instead of the old ones. Non of them show any state changes because I’ve only just updated and installed them.
Can anyone explain how/when they change state please?
I can’t find any detailed information on them.

OK, just discovered that they are read only. And the events are created automatically via the API.
So, I have registered for a power up tomorrow but no calendar entry has been created. I’ve checked when data was last received and it’s been updated since I registered for the session.
Any ideas what I’m doing wrong?