LJ usually ends up making up their own types of coding languages instead of using the ones out there already. (Note: they usually do it quite well, too.)
The only help I can give you is to familiarize yourself with the public layers and look at the documentation (which scares the crap out of me, too). (Focus on learning about the "Layout" layer. You'll need to know about the "Core," "Theme," and "User" layers, too, but if you're trying to design the look, layout is what you want.)
Of course, there's also lj_style, which might help you once you get started. "Stupidity is no excuse!"
