Hi James

Have you seen this wiki?

I only have experience with the online overpass API, http://overpass-turbo.eu/ . It has a wizard that helps you build the query you need. For your search, you could, for example, enter (in the wizard):

 ("building:levels"=* or "building:height"=* or (building=* and height=*)) in Rotterdam

In the second window, you can either use the map, or the data output.

Kind regards,
arvdk