Hardware info on main page.
2016-03-29: interfaces - wireless. I created a wireless interface based on wpi0 (named wpi0_wlan1). From Interfaces, assignments I added that as the OPT1 interface.
2016-03-29: after the reboot OPNsense 16.1.18-amd64 is running. And now network access including DNS lookups works from my "client" machine. Great!
2016-03-29: updates - another Fetch updates - new updates available, this one is a large one, and requires a reboot of OPNsense afterwards.
2016-03-29: updates - I did "Fetch updates" from System, Firmware in the OPNsense menu - which fetched an update to pkg - which I installed, so that works.
2016-03-29: WAN interface - after looking around in the web gui for a while, I managed to set up the Huawei E173 as the WAN interface, via ppp, with Telenor as a provider. While DNS lookups doesn't work from my "client" machine, they work from OPNsense.
2016-03-29: today I connected another laptop to the wired interface with a crossover ethernet cable. I had set the wired interface as the LAN interface from the console menu. After the interface was up, I started a browser and went to 192.168.1.1, which gave me the OPNsense web interface. Nice!
2016-03-28: I inserted a Huawei E173 3G modem, and got the required cuaU and ttyU devices created.
2016-03-28: I booted the OPNsense installer (from the OPNsense-16.1-OpenSSL-vga-amd64.img image) from a usb stick, and installed (quick install) on another usb stick - this worked well. On first reboot, the root path was wrong (da1s1a instead on da0s1a, because I had removed the installer usb stick) so I manually gave the correct root path, and the machine booted into default OPNsense install. It seems like the default is to use the wired interface (bge0) for WAN, and the wireless (wpi0) for LAN.