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,
Joe