Setup mode: these sounds confused me. I almost expected to find them blank, all ready to put together some layers, splits, etc. of my own. But there are quite a few pre-programmed sounds in there. Are they meant to be useful or just to demonstrate how to use setups? They seemed random and not completely "finished." In some, drum loops and arps start randomly, and don't follow the chords I'm playing. Sections of the keyboard are sometimes blank. Maybe this is one of those moments when I'm carrying over expectations from previous synths, but I expected the arps to match the chords I was playing, and to "hold" (continue) when I lift my hands, etc. More like Triton Combis? It's not a big deal. This arranger-type stuff isn't what I need or will use them for. But maybe I'm missing something about them?
The more you read about SETUPs, you will understand the great flexibility it brings to all your gear.
Unfortunately, documentation on how they are supposed to work at the preset level is a little light.
Essentially, you will find that you are going to spend more time editing and finding out how a particular SETUP works and integrating into your own SETUP. Things like the ARPs can be a little confusing for new Kurzweil owners, as they can be set up to track your finger playing, or triggered like a step sequencer.
The "arranger" type stuff is their showing you possibilities. If you are gigging with splits you may not really see the need for this type of stuff. Kurzweil call them "RIFFs" and they are a powerful feature on the PC3 series. The Riff could be a sequence you want to trigger on another piece of gear, stacked with the PC3, or the PC3 itself. They can be set up to trigger on and off on various keys and or with buttons/pedals. The ARPS are programmed not to hold, but you can program them to hold.
What I suggest you do to fast track your Kurzweil knowledge, is focus on a few SETUPs that have your interest, and ask more detailed questions about them. That way you won't have "It should work like this?" and "Why is it like that?" moments. But you will have moments thinking how deep the thing is.
Get in amongst the various Kurzweil based communities and short circuit the learning curve.