The WM coordinates point to the Hrensko terminal.
The ferry is operated by
OVPS – Oberelbische Verkehrsgesellschaft Pirna-Sebnitz.
In summer (April-October) it works from 7:45 to 21:45, in winter from 9:00 to 17:45 - see the details on the OVPS website. You can pay in EUR or CZK.