• Language codes and corresponding URL's separated with equals-to character, and one item per line:en=http://www.example.com/ de=http://www.example.com/deutsch/ fi=http://www.example.com/finnish/ de-ch=http://www.example.com/schweiz-deutsch/
• Create sitemap

The sitemap generator expects that every language version is available in each other language version. As it seems it's a complex thing to put in words what the tool does and doesn't do, so please run the tool first with the shown example data and take a moment to decypher the XML output.