Here an example how to use it:
You just need the Card “Retrieve the value of [device] for [capability] for 0 minutes ago”.
For you that would mean, Retrieve the value of [afzuiger WC] for [onoff] for 0 minutes ago.
The Retrieve card also has a token with the value, which you can check for true or false in this case.
But i guess reading your question again, i think you would just need the Turned on trigger and the Retrieve card.
