This is used internally by Ares and should match the name of the scenario file.
If you distribute more than one version of a scenario under the same name, make sure you give it a new version number. This allows Ares to compare version numbers of the same scenarios when starting net games to make sure they are actually the same.
This version number has no relationship with the version number used by the MacOS Finder.
Your name as it will appear in Ares.
Your website, if you choose.
This is where someone would go to get this version of the scenario file. You can use http://www.AmbrosiaSW.com/games/ares/addons.html as a default.