Complex sentence: She made Schloss Johannisberg available as concert venues for the festival, turning the East Wing of the building, which had not been restored after the bombing but used for indoor tennis, into a concert hall.
Split into simpler sentences: She made Schloss Johannisberg available as concert venues for the festival. She turned the East Wing of the building, which had not been restored after the bombing but used for indoor tennis, into a concert hall.