Klemens Krause (Computermusem of the University of Stuttgart) explains in the livestream from the Computermuseum how the calculating machine works. He shows how to calculate with Napier's slide rules and the calculating mechanism. He compares Schickard's calculating machine with other mechanical and electronic calculating machines.
Wilhelm Schickard was a land surveyor in Tübingen and certainly used the calculating machine for this purpose. Using logarithm tables, Klemens Krause calculates angles and distances on Schickard's calculating machine.
Calculating with Napier's slide rules is the subject of another video.