Sacrifices would have been performed at the temple. So it makes sense to assume that Ezra was seated somewhere in the temple court. This was also a very public place, at the heart of the city. If he was told about the people’s sin in the morning, then he would have sat in silence for a long time before the evening sacrifices began at around 15:00 (Exodus 12:6; Acts 3:1).1
3 As soon as I heard this, I tore my garment and my cloak and pulled hair from my head and beard and sat appalled.