So the best way to learn the basics and set up is follow this tutorial: https://youtu.be/Vfz5FKjGErQ
There’s a blender add on called blender-osm that will take open source city data and create the buildings/landscapes.
But be warned it’s not perfect and there is still clean up and editing that needs to be done. For example I cut out the water parts by hand (my personal choice to remove it) and sometimes buildings will come out floating/incomplete so I will have to clean that up myself. Not all cities have good data (for example the eiffel tower in Paris comes out as a solid block), so sometimes it’s just too hard to do some cities.