Coocoo clock

Hello, my aunt -grandmother gave me this coocoo before she passed away in 2003. It belonged to her husband (my godfather) who brought it from one of his trip to Germany back in the 40's or 50's, not really sure. We brought it from Argentina where my  aunt-grandmother was from as well as my parents. I have no idea about the brand, manufacturer, year it was built, etc, all I know It has been in our pantry for almost a decade and we recenly decide to get the price from an expert. Dimensions are, 6.5"wide x 9.5" tall x 5" deep. My aunt-grandmother told me it works, but since I have no experience with coocoos, I do not not how to make it work.