The desktop used in this guide is a Dell Optiplex 9020 Small Form Factor (SFF). This desktop features an Intel i7-4790 3.6GHz CPU, 16GB of RAM, and a 250GB hard drive. This is more than enough hardware to make a great firewall.
Inside your desktop there will be a couple Peripheral Component Interconnect Express slots (PCIe), this is where you can add things like graphics cards, sound cards, or in this case, network cards. Open your desktop and insert the network card to the PCIe slot. There might be some blank brackets that you need to remove.
Once finished, you will have multiple Ethernet connections on your desktop. Now you are ready to flash the pfSense software onto your desktop.