Arch Installation

Currently I am trying to dual boot Arch and osX on my 2012 Macbook. After I got my bootloader(rEFInd) installed and finished the installation process according to the Arch Wiki, after booting I get a missing broadcom Driver error. This is where my problem starts. I am completly new to Linux only getting it recommended to try it by friends, so my experience is limited. I can’t figure out a fix for this. The following is the entire message:

Arch Linux 4.19.4-arch-1-Arch (tty1)

username login: [ 3.564557] b43-phy0 ERROR: firmware file “b43/ucode29_nimo.fw” not found You must go to http://wireless.kernel.org/en/users/Drivers/b43#devicefirmware and download the correct firmware for this driver version. Please carefully read all the instruction on this website.

:This is pretty much the whole message. How would one go about solving this. I got the driver downloaded and I got a usb stick but I have no clue on how to transfer it. I got a working osx on the same computer if it usefull at all.

Thanks!