Install QMK:
brew install qmk/qmk/qmk
After installing QMK you can set it up with this command:
qmk setup
In most situations you will want to answer y to all of the prompts.
Now that your QMK build environment is set up, you can build a firmware for your keyboard. Start by trying to build the keyboard's default keymap:
qmk compile -kb ferris/sweep -km default
Copy the config.h and keymap.c files into the ~/qmk_firmware/keyboards/ferris/keymaps/bradsimantel directory (QMK installs at ~/qmk_firmware by default).
Then compile the .hex file:
qmk compile -kb ferris/sweep -km bradsimantel
Connect the left half of the Ferris (and only the left half) and run:
qmk flash -kb ferris/sweep -km bradsimantel -bl avrdude-split-left
You'll then be prompted to put the Ferris in reset mode before the flash happens. Repeat for the right side:
qmk flash -kb ferris/sweep -km bradsimantel -bl avrdude-split-right