hi there, zack895, maybe I can help you. I've installed a airport/bluetooth wifi card in my Mac pro, and in another one, and it's challenging, to say the least. You don't need wifi to install the OS. It's not recommended as it is too slow. Instead, plug an Ethernet cable into the back of your Macpro 4,1 to your modem/router, under system preferences, then Network, set it to use Ethernet. Turn Wi Fi off for now.Sign in to the App store and get the OS. You should have a recovery partition if you have a recent OS. Press Command/Cloverleaf key and r together on startup, and it should allow you to boot to the recovery partition, from there, you can choose to re-install the os. If you want to do Internet Recovery, that would be Option, Command, and r held down on startup. I'm assuming you have that Ethernet cable plugged in. You're going to need it as El Capitan is about 4 gigs in size, that is, if you cannot run High Sierra. Oh, and you cannot configure your airport/bluetooth card from the recovery mode. It's either there, installed and working, or not. One of the antenna connections is for Bluetooth, and the others are for wifi, depending on what kind of card you have. the antennas themselves may be labelled, and they may be tucked underneath the logic board up top, near where the wifi/bluetooth card is installed--at least that's my experience. So---if you can, get those antennae connected to the wifi card. Some have said that using antenna 2 for bluetooth, rather than the one labelled as "bluetooth" might give somewhat better results. i do know that the antenna connectors themselves are tiny, fussy and a real pain to connect. Requires a lot of patience. If you have managed to do so, congratulations, that is not a job for the faint of heart and impatient. If you have managed to download the OS, reboot and install it, and wifi icon should show up at the top of the screen and the card should show up under system report as well (under "About this Mac") If everything is in place correctly,.
good luck to you
John B
