Working from ancient memory here:
I think if you click on an item in the elements window such as "center panel", the options for that element pop up in the properties window below. You can then click on one of those options and define it, such as click on "image" with a subsequent option to import. Are you getting that far?
I think I used to take an image at my screen resolution and split it into 2 separate images - a big one for the center panel and a smaller one for the bottom panel. For a 1600x1200 screen it was something like 1600x1050 and 1600x150. Somehow I'd tell it I didn't want a top panel, don't remember exactly how, but I did need the bottom panel for the shutdown area.
One note - If the XPro is 64bit, it may not work. XP 64bit was never supported and would sometimes cause problems, but I don't remember seeing anything regarding logonstudio one way or the other. Keep that in mind though.
You may want to download one from here and tear it up to see how they're put together, you should be able to install one and then edit it:
https://www.wincustomize.com/explore/logonstudio_xp
Maybe that'll get you going or maybe someone who still has it installed will drop by. I hope I'm remembering at least half-right.