>By default, yEd tries to scale the diagram to fit the size of the paper that you print on. However, it is the responsibility of your printer to pass the correct size to yEd. Usually, there are a couple of printer specific options to control such things (in the second dialog that appears after yEd's print settings).
This approach is incorrect. Our printer can support multiple paper sizes and the user must tell the printer what to do, not the other way round.
As already indicated by other posters, it's not clear how to set the paper size on OSX.
Normal OSX applications have a Page Setup menu where you adjust this.
I can not find any Page Setup in yEd. (I'm using yEd 3.12.2)