Newbie zwave developer question: where are the files

I have a zwave device not in the library. Zwave integration sees it, but calls it unknown and can’t seem to operate it. I want to add support for it. I read this that explains I need to create some files with data from the device specs. OK, fine. But where do these files go on my raspberry pi installation for testing? I don’t seem to have anything in the /addons directory. It’s empty. Obviously I’m missing something really basic. Can anybody point me in the right direction.