Regarding setting up a MySQL shared library, you will need to edit/create the same advancedsettings.xml, but the location of your userdata folder would differ. Here are the locations of the Kodi userdata folder for each operating system.
Mac: /Users//Library/Application Support/Kodi/userdata/
Windows: Start – type %APPDATA%\kodi\userdata – press Enter
If you are asking about how to browse to a network path on Mac, I think you should be able to setup SMB file sharing from your Mac.