There are detailed instructions in the article Creating mojoPortal Skins from Artisteer HTML templates.
However, I don't think you'll be able to produce a useable skin with a trial version. I'm not even sure if you can export files from a trial version but if you can it will have watermarks on all the images.
I'm pretty sure the version info is under File > About Artisteer
"Untitled" is just the name of the file you're working with, you can name it when you save it, if the trial version allows saving.
Hope that helps,