I've been using LS for a few months now, but before that, I used it for a year or so a while back. I'm not a total noob, but manually installing a module is new territory for me.

I'm installing xInterface

So I found a module-installation tutorial which told me to edit step.rc to load my module.

Is that right? I do a search for "NetLoadModule" commands and most of them show up in the themes folders. Should I edit the theme I use's folder, or step.rc?

Nowadays the theme.rc file would be more appropriate. That particular tutorial is quite... ancient.

Yeah there are better ones at the litestep.com wiki