Sorry if necro. I found this looking for a solution for a different problem and fondly recalled having to figure this out on my own so hopefully, this will help someone who needs it. Also, I used to work in tech support so if any of this seems like it should be obvious, I don't know what you know so I am assuming that you don't know anything.
CPU:
You can put consumer grade CPUs in the sockets on this board. Anything that fits an LGA1366 socket will work. For my setup, I stuck with Xeons because I have an overly complex configuration with virtualization and thin clients and all kinds of extra nonsense that is beyond the scope of this topic (they're also stupid cheap). Throw some old i5s, or whatever you have lying around, in there and you should be fine.
RAM:
If you have one CPU don't stick RAM in the slots for the empty socket. It just won't work.
You shouldn't mix RAM types or capacities but if you must, match them in 3s. All 3 gray slots should be identical ram and all 3 black slots should match each other as well.
There is also a limit to how much you can do. I think it's something like 24 gigs of unregistered and 192 gigs of registered ram. I don't know of any home configuration that needs that much memory so if you think you will be affected by this, RTFM to save yourself a headache.
GPU:
There is a setting in the BIOS you will have to change if you want to use a discrete graphics card. While you're in there, you can also disable the onboard graphics with another setting if you want to. If you mess up and need to reset the BIOS settings, the jumpers are on the top of the board, behind the card plugged into PCIe slot 1.
You can stick an x16 card in the x8 slots if you remove the back like suggested in the thread. I used a soldering iron to melt the back out because I had one within arm's reach but I have been known to modify PCI cards instead. The process is arbitrary as long as you are careful not to damage anything. Cover exposed contacts with tape. It is also worth noting that although all of the PCIe slots are x8 in length, some of them do not have 8 rails so check which ones are which. I think the top 2 are x8 and the bottom 2 are actually x4 with x8 connectors.
I have a GTX 1050 TI powered by a 15 pin SATA Male to 6+2 PCIe Female adapter. There are a couple of free 15 pin SATA Female connectors on the rail that plugs into the DVD drive.
I also struggled for far too long with getting my card seated because there are little bits near the clips on the chassis that are intended to align the cards with the openings in the back. I had to bend one because my card takes up 2 slots.
Storage:
This thing has hot-swappable SAS ports in the front. You can plug SATA drives into SAS ports. You cannot plug SAS drives into SATA ports. Consider this when buying storage.
I use 6 SAS drives in Raid 5, a solid state boot drive and a SATA HDD I pulled out of an external drive I found at Goodwill for $5.
Power:
If you leave one PSU unplugged, you will get errors on any server OS you install. Client OSs don't care. I have both plugged in in case one fails because of the aforementioned nonsense that is going on in mine. You can leave one unplugged and switch to it upon failure if you want to extend the life of your backup one.
Network:
USB WiFi dongles work. Depending on your distro, you may have to get creative when installing drivers on a server OS. Consumer ones don't care. I use the integrated NIC and have both ports bonded. This is less system specific and more general advice but, if you are going to aggregate links, it has to be aggregated at both ends. Most consumer routers do not support this feature. Managed switches usually support this and unmanaged ones just don't care.
Audio:
Mine is handled by my graphics card and transmitted over HDMI. My speakers built into my monitor suck so I also have a USB audio adapter that plugs into some desktop speakers. You can use an audio card but, again, drivers for your OS may be a thing.
If there is anything I am missing here, I probably have no idea that it is actually a problem yet, so let me know and I'll get back to you in a year. I got so worked up with this I forgot what my problem was, to begin with.