We spent the night at Hotel International Brno (booking.com). The hotel is relatively inexpensive and ideally located: on one side the central square is 100 meters away, on the other side there is a view of the hill with the Špilberk castle. The entrance to the covered parking lot is hidden here 49.195428, 16.604816.
There are two main places to walk in Brno: the old town and the hill with the castle. Both places are on the hills and offer beautiful views. There are quite a few pedestrian zones in the old town.
The central square of the city is Freedom Square.
Parnassus fountain from the 17th century on the Cabbage Market Square.
Brno Old Town Hall with an observation deck at the top, though you have to go up on foot.
The most beautiful places are around the Cathedral of Saints Peter and Paul (XIII).
The Denisovy sady garden overlooks the city, but there is a problem. In contrast to the old town, Brno itself is a large industrial center, so the views are appropriate. The gardens have been laid out since 1805 and at that time were the first public park in Moravia and Bohemia.
After a walk in the old town, we went up the hill to Špilberk castle, a prison since 1820. Since 1960, the castle is open to the public as a city museum. It is surrounded by a fairly large park.
From the top there are views of Brno and the Cathedral of Saints Peter and Paul.
We were not looking for any specific attractions, but Brno has quite a lot of interesting architecture, so it makes sense to have a guidebook. A map of the city and other materials can be downloaded here https://www.gotobrno.cz/en/find-your-way-in-brno/for-download/.
Getting there: there is a large train station in Brno, it is convenient to get here from Prague, Bratislava or Vienna.