Homematic HmIP-BWTH: Show WINDOW_STATE in Lovelace

Hello HA-Community,
I am quite new to HA, searched quite a lot, but have not found any helpful information on my issue yet. I am moving more and more functionality from homematic (ccu3) to homeassistant and want to retire the homematic ui now - HA/lovelace is much nicer. Everything looks good, but I would like to show the param of the BTWH’s WINDOW_STATE in lovelace. I have managed to adopt lovelace to my needs, implemented the management of the underfloor heating (incl. boiler) into HA (which was not possible with homematic) via automations (also with setting of the param window_state) - but are struggling with reading the current window state from the bwth and show its current status in lovelace.

What did I miss?

Pardon, if this is a newbie question … thanks in advance