There are lots of good howtos out there to get the system installed. I followed this one, since it was for the same hardware: Build an awesome APU based pfSense Router.
Issues were with the installer software. It took a few tries to figure out I needed to run it as admin, mostly because the screens are all in German (I think). I tried other software (the one I use for the Raspberry Pi stuff) didn’t work.
Booted off the console, used the installer (after I got the right image, can’t use the iso image), and installed it. Next up, getting it on a network to use the Web interface to configure the box. Or use SSH. Maybe just plug in the laptop and see what happens. That’s half the fun anyway, or so I think.